FLACS Manual

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FLACS v9.1 Users Manual

Copyright GexCon AS

Wednesday April 27 2011


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Contents

1 Introduction 11.1 About this publication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.3 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.4 About this manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.5 What is new in this FLACS release . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

1.6 FLACS version history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

1.7 Feedback from users . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2 Getting started 92.1 Prerequisites for users . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.2 Hardware and software requirements . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.3 Software installation and setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.4 Running FLACS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2.5 Help and support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

2.6 Introductory example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

3 CASD 353.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

3.2 File menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

3.3 Geometry menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

3.4 Object window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

3.5 Grid menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

3.6 Porosities menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

3.7 Scenario menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

3.8 Block menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

3.9 View menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

3.10 Options menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

3.11 Macro menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133


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3.12 Help menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

3.13 Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

3.14 Potential bugs and problems with CASD . . . . . . . . . . . . . . . . . . . . . . . . 138

4 Flacs simulator 1414.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

4.2 The Run Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

4.3 Running several simulations in series . . . . . . . . . . . . . . . . . . . . . . . . . . 145

4.4 Output variables in FLACS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

4.5 Files in FLACS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

4.6 Input les to FLACS simulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

4.7 Output les from FLACS simulations . . . . . . . . . . . . . . . . . . . . . . . . . . 1844.8 Potential bugs and problems with Flacs . . . . . . . . . . . . . . . . . . . . . . . . . 191

4.9 Warning and error messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191

5 Flowvis 1935.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

5.2 Creating a new presentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

5.3 File menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

5.4 Edit menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202

5.5 Page menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

5.6 Plot menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206

5.7 Verify menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217

5.8 Options menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218

5.9 Help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219

5.10 Flowvis examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219

6 Utility programs in FLACS 2256.1 Geometry, grid and porosities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226

6.2 Release source modelling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234

6.3 Modifying simulation les . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

6.4 Post-processing of simulation data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240

7 Best practice examples 2457.1 Combined dispersion and explosion simulations with FLACS . . . . . . . . . . . . 246

7.2 Simulation Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246

7.3 Equivalent Stoichiometric Gas Cloud . . . . . . . . . . . . . . . . . . . . . . . . . . . 255

7.4 Dispersion simulation with wind . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259



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CONTENTS iii

7.5 Hydrogen explosions and DDT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

7.6 Pool spread simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261

8 Technical Reference 2718.1 Denitions and gas thermodynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . 272

8.2 Stoichiometric reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273

8.3 Governing equations for uid ow . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274

8.4 Wall functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276

8.5 Wind boundary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277

8.6 Combustion modelling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278

8.7 Modelling of jet sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280

8.8 Jet release of liqueed gas - FLASH utility program . . . . . . . . . . . . . . . . . . 2828.9 Numerical Schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288

8.10 Pool Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288

8.11 Porocity calculations and geometry counting . . . . . . . . . . . . . . . . . . . . . . 292

8.12 Linux Quick Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294

9 Nomenclature 2999.1 Roman letters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300

9.2 Greek letters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301

9.3 Subscripts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3029.4 Dimensionless groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

9.5 Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

9.6 FLACS variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303

10 References 305

Index 316



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Chapter 1

Introduction

1.1 About this publication

FLACS v9.1 Users ManualCopyright 2011 GexCon AS

All rights reserved

Updated: April 27 2011

Typeset in Doxygen

Printed in Norway

Intellectual property noticeNo part of this publication may be reproduced, stored in a retrieval system, or transmitted, inany form or by any means, electronic, mechanical, photocopying, or otherwise, without writtenpermission from GexCon AS.GexCon AS hereby grants permission to use, copy, and print this publication to organizations orindividuals holding a valid licence for one or several of the software packages described herein.

For further information about GexCon AS, please visit the web site: http://www.gexcon.com

Exclusion of liabilityGexCon AS has distributed this publication in the hope that it will be useful, but without anywarranty, without even the implied warranty of merchantability or tness for a particular pur-pose.

Although great care has been taken in the production of this publication to ensure accuracy,GexCon AS cannot under any circumstances accept responsibility for errors, omissions, or advice

given herein.
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2 Introduction

Registered trademarks

FLACS, DESC, CASD, and Flowvis are registered trademarks of GexCon AS.

Linux is a registered trademark of Linus Torvalds.

Windows is a registered trademark of Microsoft Corporation.

Other product names mentioned herein are used for identication purposes only and may betrademarks of their respective companies.

1.2 Preface

Computational uid dynamics (CFD) is a branch of uid mechanics that uses numerical methodsand algorithms to solve and analyze problems that involve uid ow, with or without chemicalreactions. Current use of CFD covers a broad range of applications, from fundamental theoret-ical studies involving models primarily derived from rst principles, to practical engineeringcalculations utilizing phenomenological or empirical correlations.

Many of the hazards encountered in the society, and especially in the process industries, involveaccident scenarios where uid ow in complex, large-scale, three-dimensional (3D) geometriesplay a key role. FLACS is a specialized CFD toolbox developed especially to address processsafety applications such as:

Dispersion of ammable or toxic gas

Gas and dust explosions Propagation of blast and shock waves

Pool and jet res

Thedevelopment of FLACS started in 1980 at the Department of Science and Technology at Chris-tian Michelsen Institute (CMI). CMI established GexCon (Global Explosion Consultants) as a con-sultancy activity under the Process Safety Group in 1987. In 1992, the Science and Technologydepartment at CMI became Christian Michelsen Research (CMR), and CMR established GexConas a private limited company in 1998. GexCon AS is a wholly owned subsidiary of CMR, andholds the full proprietary rights to the CFD code FLACS.

The purpose of this manual is primarily to assist FLACS users in their practical work with thesoftware. In addition, the manual aims at documenting both the physical and chemical models,and the numerical schemes and solvers, implemented in the CFD code. Ample references topublished literature describe the capabilities and inherent limitations of the software.

1.3 Acknowledgements

The development of the FLACS software would not have been possible without the generouscontributions received from supporting companies and government institutions throughout theyears. The activity started at Christian Michelsen Institute (CMI) in 1980 with the Gas ExplosionProgrammes (GEPs), and FLACS-86 was the rst version distributed to the supporting compa-

nies.



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1.3 Acknowledgements 3

Figure 1.1: The M24 compressor module represented in FLACS-86

The development of FLACS continued with the Gas Safety Programs (GSPs) and related projectsup to around 2000:

BP, Elf, Esso (Exxon), Mobil, Norsk Hydro, and Statoil supported the development of FLACS-86 during the First GEP (1980-1986).

BP, Mobil, and Statoil supported the development of FLACS-89 during the Second GEP(1986-1989).

BP, Elf, Esso, Mobil, Norsk Hydro, Statoil, Conoco, Philips Petroleum, Gaz de France, NVNederlandse Gasunie, Bundes Ministerium fr Forschung und Technologie (BMFT), Healthand Safety Executive (HSE), and the Norwegian Petroleum Directorate supported the de-velopment of FLACS-93 during the First GSP (1990-1992).

BP, Elf, Esso, Mobil, Statoil, Philips Petroleum, Gaz de France, HSE, and the NorwegianPetroleum Directorate supported the development of FLACS-94, FLACS-95, and FLACS-96during the Second GSP (1993-1996).

BP, Elf, Exxon, Mobil, Norsk Hydro, Statoil, Philips Petroleum, Gaz de France, HSE,Agip, MEPTEC, and the Norwegian Petroleum Directorate supported the development of FLACS-97, FLACS-98, and FLACS-99 during the Third GSP (1997-1999).

BP, TotalElfFina (TEF), Norsk Hydro, Statoil, Gaz de France, Philips Petroleum, Mobil andsupported the LICOREFLA project (2000-2001).

Since 2000, various Joint Industry Projects (JIPs), funding from the European Commission (EU)and the Norwegian Research Council (NFR), and support and maintenance fees (S&M) from anincreasing number of commercial costumers have supported the development of the more recentFLACS releases, including several specialized versions of FLACS, such as DESC (Dust ExplosionSimulation Code), FLACS-Dispersion, and FLACS-Hydrogen:

FLACS-Dispersion and FLACS-Hydrogen became available in 2001.



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FLACS v8.0 was released in 2003, including a test release of FLACS-Explo.

FLACS v8.1 was released in 2005.

DESC 1.0 was released in 2006.

FLACS v9.0 was released in 2008, including a test release of FLACS-Fire.

FLACS v9.1 was released in November 2009.

GexCon also develops several in-house R&D tools, including FLACS-Explo, FLACS-Aerosol, and FLACS-Energy.

GexCon is grateful to all companies, government institutions, and individuals that have partici-pated in the development of FLACS. We intend to honour these contributions by continuing todevelop the software, and thereby contribute to improved safety in the process industries.

1.4 About this manual

This Users Manual describes a family of computational uid dynamics (CFD) software productsfrom GexCon AS, generally referred to as FLACS:

The preprocessor CASD

The CFD simulator Flacs

The postprocessor Flowvis Utility programs in FLACS such as:

geo2acs , gm , and Porcalc jet and ash rdle , cole , and comerge r1le , r3le , and a1le

These programs constitute a specialized CFD tool, FLACS, or standard FLACS, designed tostudy releases of ammable gas and gas explosions in complex congested geometries, both on-shore and offshore.

A full version of Standard FLACS exhibits the full functionality of FLACS-Hydrogen and FLACS-Dispersion, whereas DESC and FLACS-Fire are separate software products. FLACS-Energy,FLACS-Explo, and FLACS-Aerosol are still in-house R&D tools. The acronym FLACS (FLameACceleration Simulator) refers to the complete package of software products, whereas the termFlacs refers specically to the numerical solver in the CFD code.

FLACS version 9.0 (FLACS v9.0) represented a major upgrade to the graphical user interfaces(GUIs), and was the rst version that ran under both the Linux and Windows operating systems.

Getting started presents a detailed example for new users of FLACS, and Best practice examplescontains further examples that highlight various applications of FLACS, including some of thespecialized versions.

Technical reference contains technical reference material.



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1.4 About this manual 5

1.4.1 Printing conventions in this manual

The symbol > followed by text in typewriter font indicates command line input, e.g.:

> command -options arguments (general syntax for commands)> find -name flacs (command line input in Linux)

The symbol followed by text in typewriter font eld input commands, e.g.:exit yes yes

The symbol indicates a path through nested menu items or dialog box options, e.g.:FileSaveScenario Ignition Time of ignition

Certain features of the software may only be accessible through text le input, and thecontent of a text le is also printed in typewriter font:

THE FIRST LINE OF THE FILE ...THE SECOND LINE OF THE FILE ...... ...

The format for describing keyboard and mouse input follows the pattern:CTRL+CCTRL+MOUSE+LEFT

The use of bold or italic font emphasizes specic words or phrases in the text.

The Nomenclature chapter lists the symbols and abbreviations adopted in this manual.

1.4.2 Special messagesWarning:

Look out for the potential pitfalls pointed out by this heading!

Attention:Be aware of practical information pointed out by this heading.

Remarks:Take notice of the points summarized under this heading.

See also:Follow up the additional sources of information suggested by this heading if required.

1.4.3 Job numbers

The typical application of the FLACS software is to quantify potential consequences of industrialaccident scenarios involving compressible uid ow, with or without chemical reactions. Propercharacterization of a particular problem may involve several simulations, and it is usually conve-nient to organize the les from related scenarios in a dedicated directory. The individual FLACSsimulations are assigned job numbers, or simulation numbers, or simply jobs. A user may forinstance type:



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6 Introduction

> run9 flacs 010100

on the command line in Linux to start a FLACS simulation for job number 010100.

The job numbers are constructed from a six-digit string ijklmn, where traditionally:

ij is the project number.

kl is the geometry number.

mn is the sequence number.

The default job number used in many of the examples in this manual is 010100, i.e. project 01,geometry 01, simulation 00. However, each of the six digits in the job number may in principletake on any integer value from zero to nine, and the references to project, geometry, and sequencenumbers only apply when the job numbers are derived from the le database in CASD.

Any updated version of this manual may be found on the FLUG web site.

1.5 What is new in this FLACS release

The following gives an overview of new functionallity and major bug xes in FLACS version 9.1.

CASD The FLACS pre-processor

Plan drawings can be placed as images inside the geometry to assist with the placingof objects or indices.

Snap points on geometry items can be used to interactively manipulate and placesingle objects, and to place multiple elements relative to each other (e.g. creatingpipelines).

Interactive drawing is facilitated by active areas on the objects, and can be used tomove, resize and rotate objects in 3 dimensions.

Selection lters make it possible to select one or more objects or primitives, eitherwithin a user dened box or according to colour.

It is possible to select multiple objects by mouse click in the geometry. Users can cut or copy, and paste , selected objects or groups of primitives between

objects and geometries. Load lters make it possible to load and display selected parts of a geometry, and

hence to comfortably work with parts of a large geometry that otherwise would re-quire more than the available memory of the computer.

Uses less memory, which enables users to work with larger geometries. Better user feedback, e.g. a progress bar is shown when reading macro les . Various problems related to the dust explosion simulator, DESC has been xed.

Flacs The FLACS simulator

Improved model for pool spread . A number of bugs have been xed in both the poolmodel and the wind boundary conditions, and the model is better validated and morestable than before.

It is possible for advanced users to change the constants in the k model.FLACS v9.1 Users Manual


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1.7 Feedback from users 7

Flowvis The FLACS post-processor

Some redesign of the user interface and bug xes.

Utilities Run Manager, geo2acs, other utility programs FLACS v9.1r3: Porcalc algorithms have been impoved to disregard nested geometry

elements (boxes and cylinders which are located inside each other). FLACS v9.1r3: cole algorithms have been improved to create geometry reports co-

herent with the way Porcalc calculates porosities, i.e. nested geometry elements aredisregarded.

Improvements in geo2acs , e.g. scaling of geometry. Smart running of porosity calculation function can be turned off in Run Manager .

A more detailed list of changes can be found in the release readme le.

1.6 FLACS version history

The following table gives an overview of the versions of the major FLACS programs which waspart of the various FLACS releases.

FLACS Flacs CASD Flowvis Porcalc geo2acs RunManager

9.1r3 2.2.8 4.9, 6.2 4.1 2.6 0.9.10 1.19.1r2 2.2.8 4.9, 6.2 4.1 2.5 0.9.10 1.19.1 2.2.8 4.8, 6.1 4.1 2.5 0.9.9 1.1

9.0 2.2.7 4.7, 6.0 4.0 2.5 0.9.7 1.08.1 2.2.6 4.6, 5.2 3.6 2.5 n/a n/a8.0 2.2.5 4.5, 5.1 3.5 2.5 n/a n/a99 2.2.5 4.4 3.4.2 2.5 n/a n/a98 2.2 4.3 3.4 2.4 n/a n/a

Table 1.1: FLACS version history

1.7 Feedback from users

Feedback on the content in this manual is most welcome, and FLACS users may submit theircomments or suggestions by e-mail to: [email protected] submitting comments or suggestion to the content of the manual, or when pointing outmisprints in the text, please indicate the relevant page numbers or sections, and the correspond-ing version of the manual (date issued).

mailto:[email protected]:[email protected]


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8 Introduction



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Chapter 2

Getting started


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10 Getting started

This chapter describes the basics of setting up the FLACS software for new users, including rec-ommendations concerning the user threshold, typical hardware requirements, and proceduresfor installing FLACS on both Linux and Windows.

2.1 Prerequisites for users

Efcient use of FLACS does not require detailed knowledge about computational uid dynam-ics (CFD). However, users should possess some experience in the application of computers forroutine tasks, such as text editing. Proper interpretation of simulation results requires adequateknowledge within the eld of uid dynamics. A suitable starting point for the novice in the eldof gas explosions is the Gas Explosion Handbook(Bjerketvedt et al., 1993) from Christian MichelsenResearch (CMR), and new users of FLACS should attend a three-day introductory course arranged by GexCon AS (http://www.gexcon.com ).

2.2 Hardware and software requirements

FLACS v9 is available on Linux and on Microsoft Windows. The hardware requirements forrunning the FLACS software depend to some extent on the size of the problem in question, i.e.the number of grid cells required to resolve the computational domain properly. Most moderncomputers, be it desktops and laptops, will perform well for small or medium sized problems.A powerful screen card may be required to handle large geometries in CASD, extra memory(RAM) is necessary for simulating large problems, and storage of large amounts of simulationdata dictates the requirements for disk space.

Hardware requirements:

Processor: Intel or AMD ix86 32 bit, Intel EM64T or AMD64. Intel IA64 is not supported.

Internal memory; 2GB or more recommended.

Free harddrive capacity: 350MB for software installation and typically 100GB simulationspace.

Graphics card using nVidia chip set. Graphics cards using for instance ATI or Intel chipsetsare in general not supported. It is recommended to purchase a graphics card with muchon-board memory. A recommended card is nVidia GTX 460 with 2 GB memory.

DVD-RW drive recommended.

High resolution colour screen (minimum 19", 1600x1200, 24 bit color depth).

FLACS v9 has been tested on the following platforms.

Linux:

openSUSE 10.0, 10.2, 10.3, 11.0, 11.1, 11.2, 11.3, 11.4

CentOS 4.6, 4.8, 5.1, 5.2, 5.3, 5.4, 5.5

Ubuntu 7.10, 8.10, 9.04, 10.04

Fedora 8, 9, 10, 12, 13

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2.3 Software installation and setup 11

Note that Fedora 11 is not supported.

Red Hat Enterprise Linux 4.6, 5.1, 5.2, 5.3, 5.4 and 5.5 is expected to be FLACS v9.1 compatiblesince it is compatible with CentOS 4.6, 5.1, 5.2, 5.3, 5.4 and 5.5.

Microsoft Windows:

XP (32 bit)

Vista (32 bit)

Windows 7

For updated hardware and software requirements, please refer to GexCons website,http://www.gexcon.com .

2.3 Software installation and setupA license server is necessary for running FLACS. This section presents FLACS installation, theFLACS Licence Serverand the FLACS Conguration Wizard that guides users through the basicsteps of setting up a FLACS Licence Server. All FLACS installations on a network acquire theirindividual licenses from a central licence server, and only one FLACS License Server shouldtherefore be running on a given network.

FLACS is distributed in a single setup le.

2.3.1 On Linux

On Linux FLACS can be installed system wide, in which case FLACS will be available to all users,or in a users home directory, in which case it will be available to this user only.

2.3.1.1 Installing in users home directory

If only one person will be using FLACS, the software can be installed in this users home directory.FLACS will by default be installed under /home/my_user/GexCon .

Save the installation package to a convenient location.

Make sure the le is executable:

> chmod u+x /home/my_user/flacs-v9.1-installer.bin

Run the installation program:

> /home/my_user/flacs-v9.1-installer.bin

Please follow the instructions given. It is recommended to keep the default parameters.

FLACS requires a license to run. The license is provided by a license server, which is installed ononly one machine on the local network. During the installation the user can choose to install:

1. Both FLACS software and FLACS license manager

2. FLACS license manager only

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12 Getting started

For a user home directory installation option 1 should be selected.

The FLACS license manager must be set up before using FLACS. Please refer to the section aboutFLACS congure wizard .

2.3.1.2 Installing system wide as super user

To install FLACS system wide, access to the system super user ("root") is required./path/to/installation is the path to the location of the FLACS installation package.

Change user to super user ("root"):

> su

Make sure the le is executable:

> chmod u+x /path/to/installation/flacs-v9.1-installer.bin

Run the installation program:

> /path/to/installation/flacs-v9.1-installer.bin

Please follow the instructions given. It is recommended to keep the default parameters.

FLACS requires a license to run. The license is provided by a license server, which is installed ononly one machine on the local network. During the installation the user can choose to install:



Option 2 can be used to install a FLACS license manager on a system not running FLACS. Alter-natively one FLACS workstation in the network can be set up to serve licenses to all other FLACSinstallations in the network.

The FLACS license manager must be set up before using FLACS. Please refer to the section aboutFLACS congure wizard .

2.3.2 On Windows

To install FLACS on Windows please double-click the installation package "acs-v9.1-installer.exe". This will start the installation wizard. Please follow the instructions given. It is

recommended to keep the default parameters.FLACS requires a license to run. The license is provided by a license server, which is installed ononly one machine on the local network. During the installation the user can choose to install:



Option 2 can be used to install a FLACS license manager on a system not running FLACS. Alter-natively one FLACS workstation in the network can be set up to serve licenses to all other FLACSinstallations in the network.

The FLACS license manager must be set up before using FLACS. Please refer to section Setting

up the FLACS license server .



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Attention:Note that running FLACS on 32bit Windows there is a memory limit of 2 GB foreach individual process. 32bit Windows has maximum of 4 GB of physical memory,

thus 2 GB is reserved for the operating system. To allow up to 3 GB for FLACSsimulations the FLACS simulator has the IMAGE_FILE_LARGE_ADDRESS_AWARE op-tion set, but a modication of the Windows operating system is also needed. Pleasesee http://msdn.microsoft.com/en-us/library/aa366778%28VS.85%29.aspxand http://msdn.microsoft.com/en-us/library/bb613473%28VS.85%29.aspxfor details. Note that doing this modication might in some situations make the computerless stable.

2.3.3 Setting up the FLACS license server

FLACS version 9.0 intruduced a new license server/manager system, which operates through anetwork protocol. This means that the license manager can be installed anywhere on the network,as long as it is available to the FLACS clients through the local network. The license managercan be installed locally on the machine where the FLACS simulation software is installed, orseparately from the simulation software. Only one license manager should be running on yournetwork, and this is where the FLACS license is installed. All other FLACS installations should be set up using this license manager.

After the installation is nished, the FLACS license conguration utility should start automat-ically. In the event that this does not happen please start the conguration utility as follows,depending on your installation.

Linux:

> /usr/local/GexCon/FLACS_v9.1/bin/run configureWizard

Windows:

> C:\Program Files\GexCon\FLACS_v9.1\bin\configureWizard.exe

Alternatively it can be started from the FLACS Runmanager Help Start Conguration Wizard.If FLACS is installed system wide (installed as root), on Linux, the license manager must berunning as user root.

The conguration utility will guide you through the setup of the license manager. The cong-uration utility is also used to congure a FLACS installation that gets its license from a licensemanager on a separate machine.

2.3.3.1 Setting up the license server on client only FLACS installation

If a FLACS license server is installed and running somehwere on the local network, the FLACS

installation must be congured to connect to the license server.

http://msdn.microsoft.com/en-us/library/aa366778%28VS.85%29.aspxhttp://msdn.microsoft.com/en-us/library/bb613473%28VS.85%29.aspxhttp://msdn.microsoft.com/en-us/library/bb613473%28VS.85%29.aspxhttp://msdn.microsoft.com/en-us/library/aa366778%28VS.85%29.aspx


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14 Getting started

Figure 2.1: Setting up the license server on client only FLACS installation

2.3.3.2 Setting up the license server on a combined license server and client FLACS installa-tion

If there is no FLACS license server available on the local network, a license server must be in-

stalled. To install a license server together with the FLACS simulation software, on the samemachine, please use the following procedure. Alternatively a FLACS license server can be in-stalled on a separate machine, with or without FLACS software. Please refer to section Stan-dalone FLACS license manager installation .

Figure 2.2: Setting up the license server on a combined license server and client FLACS installa-tion (steps 1 and 2)



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Figure 2.3: Setting up the license server on a combined license server and client FLACS installa-tion (steps 3 and 4)

2.3.3.3 Standalone FLACS license manager installation

It is possible to install the FLACS license manager only. This is useful if you would like to havethe license manager on a separate machine. To do this select the appropriate option during in-stallation (see Software installation and setup ).

To congure a standalone FLACS license manager prompt the license manager for an activationkey, by running the following command in a terminal window.Linux:

> /usr/local/GexCon/FLACS_LicenseManager/bin/FLMserver --get-ActivationKey

Windows:

> C:\Program Files\GexCon\FLACS_LicenseManager\bin\FLMserver.exe --get-ActivationKey

Send the activation key together with the IP address and license manager communication portnumber to < [email protected] > .

The communication port defaults to 25001. Please make sure that this port is available, and openon your system. If you are not sure about this please contact your system administrator.

GexCon will, based on the activation key, create a license text le. This le must be saved to:

Linux:

> /usr/local/GexCon/FLACS_LicenseManager/license/license-server.flm

Windows:

> C:\Program Files\GexCon\FLACS_LicenseManager\license\license-server.flm

Note that when using a standalone FLACS license manager, the license manager must be startedmanually each time the computer is restarted. This can be done using a startup script (not pro-vided).

In case of errors please see Error Getting Activation Key .



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16 Getting started

2.3.3.4 Renewing the FLACS license

When the FLACS license is about to run out please contact GexCon for a renewal. If the FLACS

installation has not changed then the activation key will be the same. Please start the congurewizard (available from the FLACS Run Manager help menu) and follow the procedure describedthere.

Note:When reinstalling the license it is necessary to restart the FLACS license server for the newlicense to be activated.

2.3.3.5 Potential problems with license server setup

This chapter contains a list of potential problems with the license server, and some possible

workarounds.

License server address is not localOn some systems FLMserver does not recognize its own IPaddress. This can be xed by starting FLMserver with option --add-LocalAddresses=... if FLMserver complains about server address not being local.

Start FLMserver with a graphical user interface:

/usr/local/GexCon/FLACS_LicenseManager/bin/run FLMserver --add-LocalAddresses=1.2.3.4

Start FLMserver without a graphical user interface:

/usr/local/GexCon/FLACS_LicenseManager/bin/run FLMserver-core --add-LocalAddresses=1.2.3.4

1.2.3.4 is the servers local IP address.

Error Getting Activation KeyIf a valid activation key is not reported when prompting FLM-server for an activation key, but rather an error message it is probable that an old signature leis present in the license directory. This can be the case if the FLACS installation has been copiedfrom an old computer to a new computer (Instead of being installed using the installation pro-gram). When an error message is reported, the user should make sure that the signature leis removed. The signature le is by default located at (path will be different if a non-standardinstallation path was chosen):

Linux:

> /usr/local/GexCon/FLACS_LicenseManager/license/signature

Windows:

> C:\Program Files\GexCon\FLACS_LicenseManager\license\signature

Then rerun the command above to get the activation key (rerun FLMserver program with option--get-ActivationKey ). A new, valid signature le should then automatically be created anda proper activation key reported. If the problem persists (so that the user still gets an error mes-sage even after removing the signature le once), contact GexCon describing the problem (e.g.

e-mail to < [email protected] > ).



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2.3.3.6 Starting FLACS license manager as a service on Windows

The FLACS license manager can be started as a service on Windows using the following proce-

dure.

1. Verify that the FLACS License Manager is working properly as a desktop application

(a) FLACS software and license key must be installed (see procedure above )

(b) Test run FLMserver with the graphical user interface and then quit: > "C: \ProgramFiles \GexCon \FLACS_LicenseManager \bin \FLMserver.exe"(c) Make sure to quit FLMserver, the service will not function if there is a desktop FLM-

server running.

2. Download and install the Windows Resource Kit ( rktools.exe )

(a) See the following links about Windows Services and related tools: http://search.microsoft.com/results.aspx?mkt=en-US&setlang=en-US&q=rktool http://support.microsoft.com/kb/137890

3. Install the FLACS License Manager service "FLMserver" using INSTSRV:

(a) > instsrv FLMserver "C: \Program Files \Windows ResourceKits \Tools \srvany.exe"(b) The service can be removed with > instsrv FLMserver REMOVE

(c) The path to srvany.exe might be different on your Windows installation

4. Run REGEDIT to set up the details of the service

(a) It is strongly advised to backup your current registry before editing

(b) > regedit

(c) Locate and select the FLMserver key:

"HKEY_LOCAL_MACHINE \SYSTEM \CurrentControlSet \Services \FLMserver"(d) Add one new value for FLMserver: Description

Edit New String Value : "Description" Description = "FLACS License Manager service."

(e) Add one new key for FLMserver: Parameters

Edit New Key : "Parameters" Add two new values for FLMserver \Parameters: Application and AppParam-eters* EditNew String Value : "Application"* EditNew String Value : "AppParameters"* Application = "C: \Program Files \GexCon \FLACS_-LicenseManager \ bin\FLMserver.exe"* AppParameters = --without-gui

* IMPORTANT NOTE: options start with double dashes: --without-gui The service will start automatically on reboot, it can also be started/stopped man-

ually:

Control Panel Administrative Tools ServicesFLACS v9.1 Users Manual
http://search.microsoft.com/results.aspx?mkt=en-US&setlang=en-US&q=rktools.exehttp://support.microsoft.com/kb/137890http://support.microsoft.com/kb/137890http://search.microsoft.com/results.aspx?mkt=en-US&setlang=en-US&q=rktools.exe


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18 Getting started

2.3.3.7 Restart of FLACS license manager

If restart of the FLACS license manager (FLMserver) for some reason is needed or wanted, note

that: When the FLACS core simulator acs is running for one or more job numbers, these runningsimulation jobs will not be interrupted by restarting the FLACS license manager. A CASD sessionor Flowvis session will not be interrupted when the restarted FLACS license manager is properlyrunning in less than 15 minutes after the earlier FLACS license manager process was closed. Hereit is assumed that the license level (number of simultaneous users, etc.) is the same after restart. If it takes more than 15 minutes, the graphical user interface of the CASD session or Flowvis sessionmay be put temporally on hold until the restarted FLACS license manager is properly running.

2.3.4 Setting up the FLACS environment

After installation FLACS programs can be accessed from the system menu, in the following loca-

tions:

Linux (KDE):StartApplications Edutainment ConstructionLinux (Gnome):Applications OtherWindows: StartAll Programs GexCon FLACS_v9.1Some systems may require the user to log out and restart before FLACS will appear in the systemmenu.

Desktops that do not follow the freedesktop.org standards will not install an icon in the Appli-

cations menu. This will happen on older distributions. In these cases, the user may be able toinstall icons and associations manually. Refer to your GNU/Linux distribution vendor for detailson how to customize your desktop.

2.3.4.1 FLACS User setup on Linux

For easy access to FLACS from the command line add the following text to you startup le.

If you use the csh/tcsh shell, edit or create the .cshrc le:

alias run9 /usr/local/GexCon/FLACS_v9.1/bin/run

If you use the bash shell, edit or create the .bashrc le:

alias run9=/usr/local/GexCon/FLACS_v9.1/bin/run

FLACS programs can the be started by typing eg. run9 flowvis .

2.3.5 Uninstalling FLACS

Linux: Run the program "/usr/local/GexCon/uninstall-GexCon.sh".

Windows: FLACS can be uninstalled using Control Panel/Add or Remove Programs.



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2.4 Running FLACS 19

2.4 Running FLACS

A typical simulation session with the CFD code FLACS involves several steps. Assuming FLACSis properly installed on the computer, including valid lisence les for the software, users caninitiate a FLACS session by clicking the FLACS icon on the desctop:

Figure 2.4: The FLACS icon

This should open the Run Manager window:

Figure 2.5: The FLACS Runmanager

Some of the main tasks of the Run Manager are:

Starting the Licence Manager

Starting the preprocessor CASD

Running CFD simulations

Starting the postprocessors Flowvis

The preprocessor should start when clicking the CASD icon in the Run Manager:



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20 Getting started

Figure 2.6: The CASD icon

The CASD window looks like this:

Figure 2.7: FLACS preprocessor CASD

Work in CASD often involves opening the Database window from the Geometrymenu:

Geometry DatabaseThe Database window looks like this:



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Figure 2.8: Geometry database window

Typical tasks performed from the Database window include:

Creating a new database and new geometries

Opening existing databases and geometries

Creating new materials (i.e. colours), or modifying existing materials

Creating new objects, or modifying existing objects

The New Object button, available in the Objects tab in the Database window, opens the Object

window:



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22 Getting started

Figure 2.9: CASD object window

The main purpose of the Object window is to construct a new object, or to modify an existingobject. Users can build complex objects by adding or subtracting several insides (i.e. boxes orcylinders). Any geometry can consist of one or several objects, or assemblies of several objects.An alternative way of working with geometries involves geometry import using the geo2acsutility . However, this requires that a representation of the geometry already exists on a compat-ible CAD format (typically Microstation or PDMS).

Apart from geometry building, the menus in CASD also perform the following tasks:

Denition of the computational domain and the computational grid

Porosity calculations with the utility program Porcalc, as well as porosity verication

Scenario setup, including:

Denition of monitor point locations, and selection of output variables Specication of boundary conditions Specication of vent panels and leaks Specication of fuel type Specication of ignition position and time of ignition

After dening the scenario, the next step is to run the actual FLACS simulations:

Simulations can be started and monitored with the run manager

The same operations can be controlled from the command line in Linux

> run9 flacs 010100



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Note that the Run Manager also monitors the simulations while they are running.

The nal step in a FLACS session is typically the presentation and verication of simulation re-sults with the postprocessor Flowvis, as well as data extraction and reporting. The postprocessorshould start when clicking the Flowvis icon in the Run Manager:

Figure 2.10: The Flowvis icon

The Flowvis window looks like this:

Figure 2.11: FLACS postprocessor Flowvis

Some of the most frequently used features in Flowvis include:

Verifying porosities in a geometry

Creating scalar-time plots, 2D-plots, 3D-plots, ...

Creating animations

Data reporting may also include the extraction of numerical simulation results with the utilityprograms r1-le and r3-le. These programs run only from command line input in the current

version of FLACS.



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2.6 Introductory example 25

cs010101.dat3The scenario leco010101.dat3The geometry le. This le contains a snapshot of the geometry contained in the

le database.

cp010101.dat3The porosity le, which is created by Porcalc. Please see section and Porcalc fordetails.

During the simulation a set of result les will be created:

r1010101.dat3Scalar-time output from monitor pointsr3010101.dat3Field output at selected times. Needed to create 2D and 3D plotsrt010101.dat3Simulation log le

FLACS can also create and use other les. Please see section Files in FLACS for details.

Due to the number of les created by each simulation it is important to create a good le struc-ture of directories to keep track of the les. See section Files in FLACS for details and furtherrecommendations.

2.6.2 Initialising the work directory

As FLACS creates a relatively large number of les it is important to have a good system for bookkeeping. It is recommended to start out with an empty directory.

2.6.2.1 On Linux

Make a distinct directory ( DIRECTORY_NAME ) in which you perform the exercise:

> mkdir DIRECTORY_NAME

Move into this directory:

> cd DIRECTORY_NAME

Copy geometry les (notice the space before the ".").

> cp /usr/local/GexCon/FLACS_v9.1/doc/examples/ex2/ * 00001 * .

Start up the FLACS runmanager:

> run9 runmanager

2.6.2.2 On Windows

1. Make a distinct directory in which you perform the exercise: Open the le browser ("MyDocuments") and choose File New Folder.

2. Copy les from C: \Program Files \GexCon \FLACS_v9.1\doc\examples \ex2\ 00001( 00001 means all les containing the text "00001").3. Start the FLACS runmanager by clicking the desktop icon, or go to Start Menu All

Programs GexCon FLACS_v9.1FLACS Runmanager.FLACS v9.1 Users Manual


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26 Getting started

2.6.3 Initialising and starting the preprocessor CASD

Use Run Manager Tools CASD (or click the FLACS pre-processor icon)

2.6.3.1 Open and view the geometry in CASD (Move cursor to the CASD window)

1. choose OPEN in the FILE menu OR file open < CR> OR ALT-f o (< CR> means carrigereturn, ie. the enter key)

CASD Ask for opening an existing job le

2. choose 100001.caj < OK>

CASD: Open joble 100001, using MOUSE+LEFT

3. if any error message appears click < OK>

CASD: Ignore error message = > error message CASD: Play with visualisation options, y through geometry etc.

Figure 2.12: The geometry used in example 1

2.6.3.2 Make a grid for the simulation

Make a grid (mesh) for the simulation, calculate porosities (module dim.: 25.6m x 8m x 8m, originin corner below the control room).

1. Choose SIMULATION_VOLUME from GRID menu



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CASD: To enter the extension of the simulation domain

2. Enter -16 < TAB> -8 < TAB> 0 < TAB> 40 < TAB> 16 < TAB> 16 < OK>

CASD: Volume is dened (16m out from vent, 8m to the sides; observe - sign)3. In GRID menu, choose DIRECTION X

4. In GRID menu, choose REGION and enter 56 < OK>

CASD: 56 grid cells chosen (1.0m grid size).

5. Repeat steps for Y direction and use REGION 24

CASD: 24 cells in Y-direction

6. Repeat steps for Z direction and use REGION 16

CASD: 16 cells in Z-direction

7. In GRID menu, click INFORMATION, and

to close window CASD: Check that grid dimension is 1.0m as intended

8. Choose SAVE from the FILE menu

CASD: Save geometry and grid les

9. Choose CALCULATE from POROSITIES menu

CASD: Map geometry information onto the grid, porcalc

10. Choose DISPLAY OFF in the GRID menus

CASD: Dont draw the grid anymore

Figure 2.13: Embedding the grid



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28 Getting started

Figure 2.14: Porsity calculations using Porcalc

2.6.3.3 Dene explosion scenario

1. Choose MONITOR_POINTS in SCENARIO menu OR scen mon < CR>

CASD: Dene where to measure variables

2. Click < ADD> , < EDIT> and 0.8 < TAB> 4.7 < TAB> 7.9 < OK>

CASD: Add and dene location of monitor point 1

3. Repeat this for point 2 (12.3, 4, 0.1) and point 3 (24, 7.9, 7.9)

CASD: To edit a non-highlighted monitor, click on its number

4. Click < OK>

CASD: Close MONITOR_POINT window

5. Choose SINGLE_FIELD_SCALAR from SCENARIO menu

CASD: Dene which variables to report at monitors

6. Click on < P> , drag mouse pushing MOUSE+LEFT across all monitors, < OK>

CASD: Log pressure at all three transducers

7. Repeat for < PIMP > and < DRAG>

CASD: Log pressure impulse and dynamic pressure, too

8. Click < OK> and choose SINGLE_FIELD_3D from SCENARIO menu

CASD: Dene variables for contour plots

9. Click on

, CTRL-

, CTRL-

,

CASD: Pressure, ame and velocity vectors. CTRL needed to select more than one(NB! deselect when using the scroll bar)

10. Choose SIMULATION in SCENARIO menu OR scen sim < CR>

CASD: Choose output and simulation parameters

11. Click on < NPLOT > , enter 50 < OK> , < OK>

CASD: Increase number of contour plots, return to main menu

12. Click on GAS_COMP... in SCENARIO menu OR scen gas_c < CR>

CASD: Dene gas cloud loc., size, comp. and concentration



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13. Click on < POS...> , 0 < TAB> 0 < TAB> 0 < OK>

CASD: Position of bounding box describing gas cloud

14. Click on < DIM...> , 25.6 < TAB> 8 < TAB> 8 < OK>

CASD: Dimension of gas cloud equals module dimensions

15. Click on < VOL...> , < METHANE > 91.7 < OK> < ETHANE > 7 < OK> < PROPANE > 1.3< OK> < OK>

CASD: Gas composition is dened

16. Click on < EQUI...> 1.05 < TAB> 0 < OK> < OK>

CASD: Slightly rich gas mixture is chosen ER=1.05

17. Click on IGNITION in SCENARIO menu

12.5

4.1

4.25

< OK> OR scen ign pos 12.5 4.1 4.25 OK < CR>

CASD: Dene location of ignition (12.5, 4.1, 4.25)

18. Choose SAVE from the FILE menu

CASD: Save all les, ready to run acs

19. Minimize CASD

CASD: Leave CASD for now, can be activated easily

Figure 2.15: Adding monitoring points



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30 Getting started

Figure 2.16: Choosing variables for 3D output

Figure 2.17: Adding a gas cloud and choosing the gas composition



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2.6.4 Start FLACS simulation

Select the job in Run Manager and click simulate (if job not visible, use add directory or if di-

rectory is already added, right click and rescan), check how the simulation starts up (click logle)

Figure 2.18: Running a simulation in the FLACS Runmanager

2.6.5 Study results in post prosessor Flowvis

Use Run Manager Tools Flowvis (or click the FLACS post-processor icon)1. choose ADD from Page menu (or CTRL+a)

FLOWVIS: Prepare rst page

2. click MOUSE+RIGHT , choose PLOT_TYPE and SCALAR_TIME plot

FLOWVIS: Plotting of time histories of variables

3. choose 100001 and P with MOUSE+LEFT , select all 3 monitors (drag mouse) < OK>

FLOWVIS: Plot pressure time history at all monitors

4. < RESCAN>

FLOWVIS: if simulation is running rescan will update plot

5. Choose MODIFY in the Page menu (or CTRL+m), enter < TAB> 1 < TAB> 2 < OK>

FLOWVIS: divide page into 2 plots

6. Click at lower frame, then MOUSE+RIGHT , PLOT_TYPE, ANNOTATION_ST (or CTRL+0)



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32 Getting started

FLOWVIS: show numerical values from pressure plots

7. ADD page and do the same for the DRAG and PIMP variables

8. Choose ADD in Page menu (or CTRL+a), click MOUSE+RIGHT , PLOT_TYPE, 2D... (orCTRL+2)

FLOWVIS: prepare 2D contour plot

9. Choose 100001, P, click < OK>

FLOWVIS: contour plot of pressure

10. click MOUSE+RIGHT , choose PLOT_DOMAIN, change k-index to 5 < OK>

FLOWVIS: choose XY-cut plane through ignition

11. Click MOUSE+RIGHT , choose VARIABLE_APPEARANCE change Value Range Setting toFixed

FLOWVIS: choose a user-dened xed scale for all time steps

12. Choose Min. Value as 0.05 and Max. Value as 2.0

FLOWVIS: dene the scale

Figure 2.19: Showing pressure-time curves with annotation in Flowvis



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Figure 2.20: 2D cutplane plot showing over-pressures

Figure 2.21: Setting plot domain for a volume plot

Time steps can now be changed moving the bottom scroll bar to the right, page can be variedusing the right scroll bar.

1. Repeat this method for PROD and VVEC variables (these can be plotted on the same plot)



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34 Getting started

FLOWVIS: visualize ame and velocity vectors

Try to show PRESSURE and PROD on the same page using PAGE MODIFY (use a xed scale

for PROD from 0.15 to 0.2 and change Min. Color Index to 9 and Max to 10) Now that you arefamiliar with Flowvis, try the volume plot menu to study the development of ame (PROD) andpressure Use PLOT DOMAIN to narrow the view window and see below the ceiling

2.6.6 Study the effect of ignition location

Enter CASD, open the 100001.caj job-le, save this as a new job number e.g. 100002.caj Changeignition location in order to study how pressures may vary with different ignition locations Endignition (0.5, 4.1, 4.25), (job number 100002) Your own assumed worst-case location (job number100003)

Report highest pressure achieved on monitor point

Make animation of either 2D or volume plots using the export menu (with all timesteps)



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36 CASD

The preprocessor CASD for the CFD simulator FLACS is used to prepare the input data, or jobdata , that denes a FLACS simulation: geometry model, computational grid, porosites, andscenario description. CASD is an acronym for Computer Aided Scenario Design.

CASD 4 released in 1994, use X11 graphics, but a new version is available based on QT

CASD 5 released in 2001, use Open Inventor graphics (discontinued)

CASD 6 released in 2008, use QT and Coin 3D graphics

This manual describes CASD 6, but the general functionality of CASD 6 is in principle the samefor CASD 4 and CASD 5. CASD 6 is fully backward compatible with CASD 4 and CASD 5.

3.1 Overview

This section provides a general overview of the functionality in CASD.

3.1.1 Starting CASD

Users start CASD by clicking the CASD icon in the run manager window:

Figure 3.1: The CASD desktop icon

or alternatively by executing the command:

> run9 casd6

on the command line in Linux.

3.1.2 CASD command line options

The following options can be given when starting CASD on the command line:Option Description-macro macro le name Read input from specied macro le-numMat maximum number of materials Default is 50-numObj maximum number of objects Default is 10000-numAsis maximum number of assemblies/instances

Default is 3500

-stackAsis maximum number of nested assemblylevels

Default is 8

-noLock Turns of locking on the database les. Mustnot be used if more than one user accesses thedatabase simultaneously. This option speedsup the database operations signicantly.



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3.1 Overview 37

-display and others Linux: options accepted by XTable 3.1: CASD command line options

Example:

Linux:

> run9 casd -numObj 20000 -numAsis 20000 -noLock

Windows:

> casd -numObj 20000 -numAsis 20000 -noLock

Alternatively the options can be set permanently in the FLACS Runmanager,Options

Preferences. This will only apply if CASD is started from the Runmanager.

3.1.3 The main window in CASD

Starting CASD 6 opens the main window.

Figure 3.2: The main window in CASD

The main window is divided into the following parts:

The menu bar

The icon bar



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3.1 Overview 39

Add load lters to only load parts of a geometry Snappoint toolbar: Snap points are active points on objects and primitives

Snap to corner Snap to edge Snap to face

3.1.6 The command input eld

The command input eld represents an alternative interface between the user and CASD, inaddition to the regular menus on the menu bar. The control input eld contains a scrollablecommand history list, and a current command context indicator (left side). The user controls thecommand history list from the keyboard:

UP: retrieves the previous line from the command history list DOWN: retrieves the next line from the command history list

RETURN: processes the content of the command input eld

Hence, the user can choose whether to use a menu options on the menu bar, e.g: File ExitYes(to exit and save) or to execute, after typing or retrieving, the following command in the com-mand input eld:

file exit yes yes

Command line input will in many situations be the most efcient way to work with CASD, andother sections in this chapter present additional examples on how to use this feature.

Up to 10 of the last commands given, are store between sessions.Examples: Using the command input eld in CASD

Select a box primitive in an object. The following command moves the box to (2, 2, 2), andwould cause the properties dialog to be shown

edit properties 2 2 This is because the position is not completely specied. The user does not have to

specify all parameters, but must include all values for the parameter specied.

If the user wants to edit one of the last parameters in the dialog, it is not necessary to specifyall the parameters in front. The parameter name can be used to indicate which parameterto edit

edit properties size 2 2 2 vol_por 0.5

The user can also supply the answer to a question in the input eld. To delete an assembly/instance, CASD will ask to conrm the operation. To avoid the question dialog, typethe following command

geometry delete yes or shorter: g e d e y

To direct the output from a list to a le, append the le name after the list command. Forinstance, to list geometries in the database, enter the following command, which will createthe text le outfile.txt

geometry list outfile.txt



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40 CASD

3.1.7 The geometry window

The geometry window in the main window displays the geometry, the computational grid and

scenario paramters. In addition to the options on the View menu, there are several ways of manipulating the view:

Rotation: MOUSE+LEFT

Panning: CTRL+MOUSE+LEFT

Zoom: MOUSE+SCROLL

Rectangle zoom: MOUSE+RIGHT+SELECT

Splitting and closing views: MOUSE+RIGHT+SELECT

The use of these features are quite intuitive, and they will not be described in more detail in thismanual.

3.1.8 The status eld

The status eld in the main window contains information concerning the active database, project,geometry, grid, and units.

3.1.9 Geometry window icons

Each geometry window has its own icon bar underneath.

Figure 3.3: Geometry window icons

The geometry window icon bar has following the following functions.

Switch between walk viewer and y viewer

Selection mode on

View mode on

Store camera position

Re-store camera position

Seek to picked point

View all

Switch between parallel and perspective projection

Turn axis on/off



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3.1 Overview 41

View along X axis

View along Y axis

View along Z axis

3.1.10 Coordinate eld

The coordinate eld below each geometry window shows the position of the mouse pointer inthe geometry [meters], when the geometry selection mode is active. If clicking MOUSE+LEFT theposition shown becomes more accurate and the coordinates are copied to the system clip boardfor pasting in CASD or other programs.

The font type and size of the text in the coordinate eld can be set by the user by clickingMOUSE+RIGHT in the coordinate eld, and selecting Set font....

3.1.11 Files in CASD

CASD stores job data on a set of les. For the arbitrary job number 010100, the most importantles are:

Header le, 010100.caj: ASCII le created by CASD; denes the cs, co, cg, and cm les used by CASD.

Geometry le, co010100.dat3: binary le created by CASD; contains a list of primitives froma CASD database that dene the geometry; used by Porcalc and Flowvis.

Grid le, cg010100.dat3: binary le created by CASD; denes the computational mesh; used

by CASD, Flacs, and Flowvis. Porosity le, cp010100.dat3: binary le created by Porcalc (typically from the Grid menu in

CASD); denes the porosities for each grid cell; used by Flacs and Flowvis.

Polygon le, cm010100.dat3: binary le created by CASD; denes the polygon model; used by Flowvis (if the le exists).

Scenario le, cs010100.dat3: ASCII le created by CASD; denes the general scenario (mon-itor points, output variables, fuel region, pressure relief panels, ignition position, etc.); used by CASD, Flacs, and Flowvis.

The geometry le is also called the obstruction le, or co-le, and is not a direct input to the simula-tion; it is however used by Porcalc when generating the porosity le. The File menu in the main

window contains commands for creating, opening, and saving the various job les. See sectionFiles in FLACS for further information.

3.1.12 Working with geometries in CASD

To implement the geometry model in CASD can often be the most time consuming part of aproject. For modern process facilities it may be possible to import a geometry from an existingCAD model, but for many installations the geometry must be constructed manually from draw-ings, photographs, etc.

A large projects, such as a full probabililistic analysis, can involve hundreds of CFD simulations,and each simulation will typically produce 10-15 different les. Hence, it is very important to

organize the les in a well-structured manner.



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42 CASD

The building blocks in a CASD geometry are instances of objects. The structure within an objectis a so-called Constructive Solid Geometry (CSG) model, where simple solid primitives (boxesand cylinders) are combined by Boolean operators ( unions and left differences ).

Objects in CASD can be either global or local . Several geometries can contain instances of thesame global object, whereas a local object can only be included in the geometry where it wascreated. It is generally recommended to use global objects, and avoid the use of local objects.

The list of information required to implement a typical process facility, such as an offshore oilplatform or an onshore process plant, is quite extensive:

Plot plan

Sectional drawings

Piping plan

HVAC layout

Cable trays layout

Framing plans

Cladding

Deck plan

Most FLACS users nd it convenient to dene standardized axis directions, and the followingconvention is used by GexCon for typical process facilities:

East-West along the x-axis, with positive x towards the east.

North-South along the y-axis, with positive y towards the north.

Up-Down along the z-axis, with positive z pointing upwards.

This results in a conventional right handed coordinate system, where the lower south-westerncorner of the facility coincides with the origin (0,0,0).

Each object in a CASD database is assigned a material property, and each material is assigned acolour hue from the 0-360 colour circle. Many FLACS users nd it convenient to assign certainhues to various structural elements, and the following convention is used by GexCon for typicalprocess facilities.

Hue Colour Description0 Red solid walls and decks30 Orange pressure relief and and

louvred panels60 Yellow grated decks120 Green anticipated congestion180 Cyan equipment200 Light blue structure220 Medium Blue secondary structure250 Dark Blue piping300 Pink equipment

Table 3.2: Colour convention used by GexCon



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3.2 File menu 43

A standardized colour scheme makes it more straightforward to review geometries from oldprojects.

3.1.13 About congestion, connement, and vents

In order to have a good representation of the effect of obstacles it is important that they are wellrepresented geometrically by the chosen grid. In most practical situations it will not be possibleto represent the smaller obstacles on the grid, these should still be included since they may betreated by proper sub-grid models. Larger obstacles like the oor (or the ground), the ceiling, thewalls and larger equipment will be resolved on-grid. This means that they will be adjusted tomatch the grid lines.

The most challenging geometry to represent properly is repeated obstacles of the same size andspacing as the chosen grid resolution, in such cases the user should consider to change the grid toachieve a better representation. If this type of geometry is dominant it is of vital importance forthe accuracy of the result that the representation is good enough. In cases where such a geometryis not dominant one may pay less attention to how it is represented. For normal offshore modulesthere will be a range of subgrid sized obstacles which are more or less randomly distributed inspace.

A subgrid obstacle is a geometry object where subgrid contributions to turbulence and amefolding is applied. Such contributions are applied to objects with a dimension of less than 2control volumes.

In many experimental setups one will nd repeated obstacles of the same size. The basic researchon gas explosions past many years now has focused on the effect of obstacle arrays, perhaps toa greater extent than on the effect of more realistic geometries. Both categories are important inorder to be able to validate tools like FLACS.

It is important to represent the vent openings of a semi-conned geometry properly. If obstaclesclose to the outer boundaries are adjusted to match the grid, the effective vent area may be af-fected. In order to verify that the representation of the vent openings is as good as possible theuser should check the porosity elds (using CASD or Flowvis).

3.2 File menu

3.2.1 New

Shortcut: CTRL+N

Creates a new simulation job based on the selected scenario template .

The New command in the File menu creates a new empty job. If there were unsaved changes tothe current job, a dialog box is displayed, asking about saving the changes.

3.2.2 Open

Shortcut: CTRL+O

This command opens an existing set of simulation les. The default simulation les selection isdened in the header le ( .caj).

The Open command in the File menu opens an existing job.



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3.3 Geometry menu 45

connected to a database. The Save and Save As commands in the File menu writes the geometryto the geometry le.

The building blocks in a CASD geometry are instances of objects. Objects can be global or local.Several geometries can contain instances of the same global object, while a local object only can be included in the geometry where it was created.

Instances can be grouped under assemblies. Several levels of assemblies can be created. Eachinstance and assembly has a transformation matrix. The position, scale, and orientation of aninstance is the result of the matrices on all levels above the instance, in addition to the matrix forthe instance itself.

Each geometry is a member of a project. The project is the top level in the CASD data structures.A project can own a number of geometries.

Instances and assemblies can be made invisible and visible using the following commands:

CTRL+I Make the selected assembly/instance invisible

CTRL+SHIFT+I Make the selected assembly/instance visible.

Use the Position command in the Geometry menu to change the position of the selected assemblyor instance.

3.3.1 Geometry Database

The rst option on the Geometry menu in CASD opens the Database dialog window.

Figure 3.4: The geometry database window in CASD

In the Database dialog window the user can:

Create a new database, project, geometry, or object.

Connect to or save an existing database.

Open or save existing, projects, geometries, or objects.



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46 CASD

Insert instances in a geometry.

Dene new materials or edit existing materials.

The Database dialog window has a refresh button. This can be used if the data in the database isout of sync with the contents in the database dialog window.

Note:A database can have up to 99 projects, and each project can have up to 99 geometries.

3.3.1.1 Geometry tab

On the Geometry tab the user can create, open and manipulate projects and geometries. Projectscan be renamed and deleted, geometries can be renamed, copied and deleted.

3.3.1.2 Objects tab

On the Objects tab the user can open, rename, change material of, create instance of, move anddelete existing objects. There are also buttons for creating new objects and saving the list of objects to a text le.

The New Objectbutton in the Database dialog box opens the object window .

The Filter text eld can be used to search for object names. The asterisk ( symbol) will matchany number of arbitrary characters, so typing the text object-22 will show all objects withnames containing the string object-22 .

Warning:It might be necessary to save the geometry to the database by clicking the Save Geometry button on the Geometry tab before an object can be deleted using the Delete button.

3.3.1.3 Materials tab

Each object in a CASD database is assigned a material property, and each material is assigned acolour hue from the 0-360 colour circle. To dene a new material click the New Material button.

The new material is dened by a name and a hue, a value between 0 and 360.



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Figure 3.5: Colour wheel with the most commonly used colours marked

3.3.2 Creating a CASD database

To create a database choose Geometry Database or type geometry database . The Geome-try Database window is shown. Click the Connect button. A le selection dialog box is displayed.Move to the directory where the database should be created, and write the name of the database,e.g. my_database.db . Alternatively the database can be created using the command input:database create my_database.db , which will create a database in the current directory.

If the Geometry Database window is not open, choose Geometry Database. Use the New Project button to create a new project, or the Open Project button to open an existing project.When a project is opened, a new geometry can be created clicking the New Geometrybutton, oropen an existing geometry clicking the Open Geometrybutton.

When an existing geometry is opened, the assembly/instance structure and all objects andmaterials used are loaded into the CASD program. If the geometry contains many assemblies/instances, you may get an error message indicating that there were not room enough inthe CASD data structures. See section CASD command line options for information on how youcan use command line options to allocate more memory for these structures.

3.3.3 Connecting to a database

To create a new database, see section Creating a CASD database .

To connect to an existing database choose Geometry

Database or type geometry

database . The Geometry Database window is shown. Click the Connect button. A le se-



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lection dialog box is displayed. Select the CASD_DB le on the database directory you want toconnect to.

If you enter the le name in the command input eld, the path must be encapsulated in apostro-phes, for instance:

database connect "MyCasdDB.db/CASD_DB"

3.3.4 Creating a new or opening an existing object

You can create a new object clicking the New Object button on the Objects tab in the GeometryDatabase window, or open an existing object using the Open button.

When you have completed the New or Open Object command, the object window is displayed.

3.3.5 Selecting a node and a subtreeAt any time, a part of the binary tree is selected. It may be a single node, or a subtree containingseveral nodes. If a subtree is selected, the top node is referred to as the selected node. In thepostx string, the top node is the rightmost node in the subtree.

The selected subtree is highlighted in the graphic window, and underlined in the message area.There are two different methods for selecting a subtree.

1. Click MOUSE+LEFT while pointing at a primitive. If several primitives are hit, they areplaced on a stack (list). Only one primitive is selected at a time. Press CTRL+TAB commandto parse this stack.

2. Use the following commands:CTRL+L Select the previous instanceCTRL+R Select the next instance

3.3.6 Maintaining a CASD database

The dbfutil program is available for creating and maintaining CASD le databases. If an erroroccur when loading or saving a geometry to the database dbfutil will in many cases be able toremedy the problem. Please see below for details.

Linux:

> run9 dbfutil database command [option]

Windows:

> dbfutil database command [option]

The usage of this program is described in table Using the the dbfutil program . Make sure that noother users are connected to the database when you execute this program.

Command Descriptioncreate Create databasedestroy Destroy databaseforce Destroy database, override any errors



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dellock Delete all locks. Use this command if les inthe database are still locked after a crash inCASD

restoredep Restore dependencies. For each object in thedatabase, there is a le containing a list of allgeometries that contain instances of theobject. (Executing the Information commandin the File menu in the Object dialog lists thecontents of this le.) This le is used fordetermining if the object can be deletedwhen you execute the Delete Objectcommand in the Database menu. CASDupdates these les when required. But if aproblem should occur for some reason, therestoredep command might help. It updatesthe le mentioned above for all objects in thedatabase.

restorehead Restore header les. This command resetsthe process log le for the database. This lecontains a list of (CASD) processes currentlyconnected to the database.

list List the content of all table les, e.g. list Olists all objects:

P List the content of all project table les.

O List the content of all object table les.

M List the content of all material table les.

G List the content of all geometry table les.

L List the content of all local object tableles.

U List the content of all objects-used tableles.

A List the content of all asis table les.

Table 3.3: Using the dbfutil program

We strongly recommend that you make backups of your databases on a regular basis.

3.3.6.1 Fixing database error using dbfutil

In some situations an error like the following might be shown in CASD:

(81) Error occurred when inserting/updating the geometry on the database.Error writing asis.(CAdbGeo::save)

(CAdb::saveGeo)



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50 CASD

To x errors when loading or saving a database geometry dbfutil can be used with the followingoptions.

Linux:

> run9 dbfutil database dellock> run9 dbfutil database restoredep> run9 dbfutil database restoredhead

Windows:

> dbfutil database dellock> dbfutil database restoredep> dbfutil database restoredhead

Warning:

Make sure no other users are connected to the database when running the above commands.

3.3.7 Local objects

Local objects consist simply of one box or one cylinder. Use local objects to dene entities likewalls, oors etc. Dene global objects for more complicated things.

The name of a local object must start with an underscore character (_).

The Local Object command in the Geometry menu creates a local object, and one instance of it.You can of course create several instances of the local object using the Instance command.

The Local Object command has two sub choices, Box and Cylinder. Select the appropriate primi-tive type.

CASD will rst ask for the material name. Enter the name of an existing material. The materialdecides the colour of the object. If you havent dened any materials, use the New Materialcommand in the Geometry Database window to create one.

CASD will then ask for the sizes and porosities for the primitive. CASD creates an instance of theobject in (0, 0, 0). Use the Position or Translate command to move it to the correct position.

You can use the Properties command to edit material, sizes and porosities for a local object. TheRename command changes the name of the object.

3.3.8 Global objects

A global object is edited in a separate object window . All the commands described in this chapterrefers to the menus in the object window.

Global objects can have instances in several geometries. The structure within a global object is aconstructive solid geometry (CSG) model where simple solid primitives are combined by meansof Boolean set operations. The primitives and operations are nodes in a binary tree where theleaves are primitives and the internal nodes are operations.

Boxes, cylinders, ellipsoids, general truncated cones ( GTC) and complex polyhedrons ( CP8) arethe primitive types supported. The box primitive includes planes as a special case. Availableoperation types are union and difference.

Warning:

Only boxes and cylinders should be used in by default, but ellipsoids, general truncated



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cones and complex polyhedrons can be used in special cases. These latter primitive typeshave the following important limitations:

No subgrid models, thus not contribution to turbulence and drag force

Porosity calculation takes a long time for these primitive types. There should be nomore than 100-200 of these primitives in any given geometry

Figure 3.6: Supported primitive types

A root is a subtree that is not part of another subtree. The object typically contains several rootsduring editing. But it must contain only one root when it is saved.

The postx string represents a way of visualising the binary tree dening the object.

The postx string for the open object is displayed in the message area in the object window . Theselected subtree is highlighted.

A material is assigned to each object. The material decides the colour of the object.



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3.3.10.1 Adding an instance

To add an instance of an object, use the Instance command in the Geometry menu. CASD will

ask for the object name. You must enter the name of an existing object. The instance is placed in(0, 0, 0). Use the Position or Translate command to move it to the correct position.

Alternatively the Instance button on the Objects tab in Geometry Datbase dialog can be used.

When a new instance is created, it is placed in the geometry structure depending on what wasselected on forehand. If an instance was selected, the new instance is placed after that instanceunder the same assembly. If an assembly was selected, the new instance is placed under thatassembly.

3.3.11 Local object

Creates a local object in the current geometry.

3.3.12 Delete

Shortcut: Del

Deletes either the currently selected instance, local object, or the current assembly.

Warning:

If deleting an assembly all instances within the assembly will be deleted.

3.3.13 List

Lists all assemblies and instances in the current geometry, including modied positions.

3.3.14 Copy/cut & paste

Shortcut: CTRL+C

Shortcut: CTRL+X

Shortcut: CTRL+V

Copy/cut & paste can be used to copy parts of the geometry and paste it into a different assembly,or into a different database. If a selection lter with a bounding box is used, only the parts of thegeometry within the bounding box is copied or cut. This means the cut function can also be usedto easily remove parts of an object, or for instance create a hole in it.

When pasting, the new assemblies and instances are created under the currently selected assembly, or in the same assembly as the currently selected instance. If the use of a bounding box causesobjects to change, new objects will be created.

Geometry copied from the geometry view can be pasted into the object editor. You can optionallyapply the assembly and instance transforms to the pasted primitives.

The selection lter is not available in the object editor, but

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