Fluent 2019 R1 Product Updatefrontis.co.kr/wp-content/uploads/2019/05/2019R1-Fluent-1.pdf ·...

1 © 2018 ANSYS, Inc. December 31, 2018 ANSYS Confidential

Fluent 2019 R1 Product Update


User Interface


New User Interface Look

User-Selectable Themes

Default

SpaceClaim 2016

Fluent 19.2


Graphics Color Scheme Preference


Preprocessing


Single-Window Workflow in Fluent

Geometry Surface Mesh Region Extract Volume Mesh Setup/Solve Post

SpaceClaim

Workbench (Beta)


Task-Based Watertight CAD->Mesh Workflow

• Streamlined general-purpose workflow for watertight CAD− Extensions to dirty geometry in upcoming releases

• Embeds many best practices to minimize trial-and-error / user configuration

• Ability for users to:− Modify the workflow and save / re-use for other geometries

− Create and distribute custom workflows

• Record and replay the workflows

• Robustly process upstream changes


Watertight Workflow New Features - 2019R1

❑ Local Sizing• Face Size, Body Size, BOI, Curvature,

Proximity

❑ Periodic boundary Support❑ Assembly workflow, support of

models without shared topology• Perform share topology within the

workflow

❑ Parallel Option for Mosaic (Hex-Poly) ❑ Field-level (context sensitive) help❑ Send to Fluent Option in Spaceclaim❑ Workbench Support (Beta)


Parallel Hex-Poly Volume Meshing (2019 R1)

• Particular benefit for meshes larger than 10-20Million cells

• Up to 2.5 Million cells/min with 16-way parallel

• Typical memory requirement: ~3GB / Million cells

• Limited to Watertight Geometry Workflow initially


Parallel Hex-Poly Test Case - Generic Combustor


Parallel Hex-Poly Test Case - F1 Car

1* Run on a machine with 512 GB RAM ** Priority for robustness improvements was given for upto 16 cores


Fault-Tolerant Workflow (Beta)• New task-based CAD -> Mesh

workflow for dirty geometry (holes, intersecting surfaces, etc.)

• Specific tools available for off-body wake refinement, etc.


Selective Mesh Check

• Selectively choose particular cell-zones / characteristics for Mesh Check


Workflow Enhancements


Expressions in Fluent

Example: Parabolic Inlet Velocity

• Functions of location, time, solution variables• Various physical constants / mathematical functions• Availability where profiles or parameters can be used• Similar to CFX / AIM

Note: User interface may change


Simple to implement a new “fully developed parabolic flow” boundary condition.

Expressions: Parabolic Inlet Profile Example


Expressions: Unsteady Outlet BC Example

Fluent unsteady compressible tutorial

Sinusoidal Outlet PressureP_out = Po + P(t)Po = 0.737 atmP(t) = 0.12 atm @ 350 Hz

Before Expressions…

#include "udf.h"

DEFINE_PROFILE(transient_pressure, thread, position)

{

float t, pressure;

face_t f;

t = RP_Get_Real("flow-time");

pressure = (0.12*sin(2200*t)+0.737)*101325.0;

begin_f_loop(f, thread)

{

F_PROFILE(f, thread, position) = pressure;

}

end_f_loop(f, thread)

}


Using Fluent Expressions

No UDF required!


More Flexible Mesh Adaption

• Separate criteria for Refinement vs. Coarsening

• Criteria can be based on Boolean expressions, or cell-registers− Enables sophisticated criteria derived from multiple

fields, regions, etc.

• New control to create “buffer” layers around refinement region− Reduce cell regions “flipping” between refinement and

coarsening


Streamlined Adaption Inputs

Register Definition

Adaption Criteria and Controls

Register and Adaption Criteria

Register Manipulation

Adaption Controls

19.22019 R1


Consolidation of Field-derived Cell Register Types

19.2 – Separate GUIs for gradient-based and iso-value based registers

2019 R1 – One GUI for field-value-based registers with streamlined inputs


Easily Copy Settings to Other Sessions

• Drag and Drop

• Copy / Paste

• Import / Export

• Support for• Boundary and Cell Conditions

• Report Definitions

• Expressions

• Graphics Objects

Also:• Drag / Drop Case / Data files onto graphics window to load• Drag / Drop Graphics objects into graphics window to display


Text Command Auto-Completer

• Functions similarly to tab-completion in other environments− <Tab> expands to a unique match, or prompts for selection from multiple matches

• Matches:− Text menu/command names

− File system locations

− Zone names (when prompted)

• Enable in the Preferences dialog


Surface Exposure and Editing

• Surfaces now appear in the Outline View

• Right click “Surfaces” to create

• Right click on surface names for various operations− Edit surface definition

− Display surface(s)

− Multiple surface selection can be grouped


Other User Interface Enhancements

• Text Interface Auto-Complete

• Copy / Import / Export Boundary Conditions and Post Objects

• User Interface Localization

• Progress Indicator


Solver Enhancements


Solver Robustness Improvements

• Coupled Pseudo Transient Used by Default− For most single phase steady applications in 2019 R1

− Incorporates some enhancements to the PT method itself

• Aggressive Coarsening Improved− Enhancement of Aggressive Coarsening option first introduced in 19.0

− Better convergence without performance penalty

− Used by default for Coupled Pseudo Transient in 2019 R1

• Improved behavior on non-uniform meshes− Default use of Improved Rhie-Chow flux for non-VOF cases

− Reduces or eliminates unphysical reflections sometimes observed with Hexcoremeshes.


Boundary Conditions

• Prevent Reverse Flow at Pressure Inlets

• New single text command to create conformal or non-conformal periodic interface/mesh/modify-zones/create-periodic-interface

− Fluent will automatically check if zones are conformal or not and create either Periodic boundary or Periodic non-conformal interface as appropriate.


Transient Enhancements


Pressure-Based Transient Solver Performance• NITA Accelerated Time Marching for single-phase LES flows

− >5x speedup in comparison to SIMPLE-C for Volvo LES bluff body case

− Similar solution accuracy to SIMPLE-C

• Equation Order optimization for variable-density flows− Combustion solutions can be solved up to 2X faster by taking

advantage of improved equation solve order and reducing sub time-step iterations/solve/set/equation-ordering optimized-for-volumetric-

expansion

Solver Time, s Speed up

SIMPLEC 53648.732 (15 h) 1

NITA 22922.716 (6 h) 2.3

NITA with Accelerated Time Marching 9203.501 (2.6h) 5.8


New Time Stepping Methods

• Fixed-Periodic− For periodic flows (esp. rotating equipment)

where it is desirable to control the simulation based on a fixed division of a period of interest

• CFL Based− New automatic time step adjustment to satisfy

CFL criterion

− Compatible with both 1st and 2nd order transient*

New

New

*If using a case from a previous version, you will need to turn on the variable time stepping formulation for 2nd order:/solve/set/second-order-time-options yes


Fixed Periodic Time Stepping

• For periodic flows (esp. rotating equipment) where it is desirable to control the simulation based on a fixed division of a period of interest.

• User Specifies− Period (or frequency)

− Time steps to use per period

− Number of periods to simulate

• Fluent calculates− Time step size

− Number of Time Steps


CFL Based Time Stepping

• Optimizes time step size in transient simulations based on a CFL condition.

• Especially useful when mesh adaption is used to capture fine details of transient flows

• User Specifies− Target Courant Number

− Ending time of simulation

− Min. and Max. Time step sizes

− Min. and Max. Time step adjustment factors

− Number of initial time steps before adjusting

− Initial time step size

• Fluent calculates− Time step size required to satisfy specified Courant

number condition


Flow-Time Monitoring and Postprocessing

• For cases with non-constant time steps, repeated tasks can be specified to occur on the basis of number of time steps.− Report File / Plot Update

− Case/Data Autosave

− Execute Commands

− Animation Frame creation

• Note that Fluent will not alter the time step to hit the precise interval. Operation is performed at the nearest next time step.


Accelerate SBES with Specified RANS Update Interval

• 20-30% of wall clock time is spent in turbulence model

• Most time-consuming part is computation of RANS solution

• SBES model can be accelerated by specifying an Update Interval for the k-omega equations to avoid solving RANS every time-step

• Very minor impact on results for low CFL numbers

• DrivAer case using Update Interval of 5 has shown overall wall-clock reduction of up to ~25%


Applications


Spray Characterization and “Playback”

• Sample a DPM flow and use a histogram approach to capturing the particle characteristics with a reduced data set

• Allows more efficient subsequent DPM simulations by using fewer parcels to represent the particles

• Target application− Use VOF->DPM for detailed spray breakup

simulation

− Use Sample Reduction to create moderate-size injection files for later simulations


Aftertreatment Other Filming Sprays

• Stripping / Edge Separation of Lagrangian Wallfilms

* “Liquid Film Formation by an Impinging Jet in a High-Velocity Air Stream”, M. Arientiet al., Journal of Engineering for Gas Turbines and Power, March 2011, Vol 133


• Near field: LES or hybrid RANS/LES → sound sources

• Mid-field: Sound propagation in non-uniform flow + reflection

• Far-field: Sound propagation in uniform flow to locations typically outside computational domain (Ffocs-Williams-Hawkings)

Mid-Field Acoustic Propagation

New Wave Equation Solver Targets:• Mid-field acoustic propagation with

reflections and/or non-uniform flow conditions

• Ex: bluff body appendages, internal flows

Provides an alternative to relying on solving compressible flow to capture mid-field propagation details


Corrosion and Electro-chemical reactions

• Electro-chemical parameters (such as used in corrosion simulations) often depend on temperature

• Specify Butler-Volmer / Tafel parameters as functions of temperature or through UDF


Induction Heating Using System Coupling• Coupled Fluid / Electromagnetic Simulation

− Maxwell Eddy Current Solver coupled with Fluent Steady or Transient

− 3D exchanges of fluid & solid temperature and Joule heating

− Efficient Unsteady Co-Simulation

• Co-simulation solve allows for disparate physical time scales

• Electromagnetics can be steady from fluid dynamics perspective

• Maxwell update frequency is user controllable (solution speed)

− Supported through Command Line System Coupling infrastructure


Erosion: Abrasive Erosion

• For dense granular flows, abrasive erosion becomes significant

• In 2019 R1 abrasive erosion can be simulated using Erosion with Dynamic Mesh with multiphase simulations Single-Phase Multi-Phase

(incl. Abrasive Erosion)After 100 sec


Erosion: Granular Phase Shielding

• Granular phase accumulation near the wall reduces the erosion rate due to shielding effects

Shielding ON Shielding OFF

Erosion Rate (kg/m2-s)


Conjugate Heat Transfer / Shell Conduction

• Shell Information can be included in case file to improve case read speed with large numbers of shells− Not enabled by default

− Known Limitation: Reading a case file with shell information into Meshing Mode will result in a crash

• Implicit coupling is now used for Fluid/Solid mapped mesh interfaces− Can yield dramatic improvements in convergence

Cores Elapsed(mins)

(No Shell Information)

(Legacy Format)

Elapsed(mins)

(With Shell Information)

(Legacy Format)

Reduction in Elapsed

Time (%)

24 35.60 11.64 67.30

48 16.96 8.03 52.65

96 11.25 6.1 45.77

192 8.43 6.06 28.11


Monte Carlo Radiation Modeling

• Support for Mapped Mesh Interfaces− Only completely overlapping regions are considered

• Compatibility with Solar Load model is added− Use solar calculator to get solar loads and sun director vector

for use by Radiation models

• Performance Improvements


Physics


Chemkin Physical-Space Flamelets in Fluent

• Premixed flamelet-generation in Fluent assumes an SDR profile.

• Using Physical Space avoids this assumption− Impact on temperature and flame properties will depend

on combustion conditions

• In 2019 R1 Chemkin-based flamelets can be generated from the Fluent UI− Seamless integration with the Fluent FGM model

− Results are the same as premixed flamelets generated in ANSYS Chemkin-Pro UI using the Flame Speed Calculator T

v 1-D Freely propagating Flameas modeled in ANSYS Chemkin-Pro


Example showing potential impact of physical space flamelet

• Comparing Fluent premixed flamelet vs. Chemkin premixed flamelet− Laminar flame to remove impact of turbulence (zero variances in FGM model)

− Compare with Finite-rate chemistry (FRC) solution

ChemkinFlamelet

FRCFRC Fluent Flamelet

OH mass fraction in a premixed laminar methane flame

Comparing Finite-rate Chemistry (FRC) vs. Premixed FGM with zero variances


Thickened Flame Model (TFM) has been improved

• Improved theoretical basis allows prediction of light-around

• Results for 5-burner Ignition Case (LES) with TFM predict the correct sequence

Experimental data from:Barré et al., C & F 2014

Burner number 5 4 3 2 1

Animation for 2019 R1 TFM: Temperature at midplane


Generalized k-ω (GEKO) Model

• Formulation of k-ω which can be tuned based on selection of four “free coefficients” corresponding to particular flow characteristics:

( ) ( )

+

+−=

+

jk

t

j

k

j

j

x

k

xkCP

x

kU

t

k

( ) ( )

+

+

+−=

+

j

t

j

jj

k

j

j

xx

xx

kFFCP

kFC

x

U

t

23

2

2211

( ),

,max Real

tCS

k

=

• CSEP – changes separation behavior

• CMIX – changes spreading rates of free shear flows

• CNW – changes near-wall behavior

• CJET – Optimizes free jet flows

Theses coefficients are used to compute functions F1, F2, and F3

• Allows use of a single core model for varied applications, rather different models for different applications


DPM/DEM Wall Force Export

• DEM particles in silo

• DPM particles in bend

Wall normal pressure vs silo height @ 4.1s

before silo discharge

Variation of maximum wall force components

in an elbow versus iteration number


Cavitation / Evap-Cond Mass Transfer• Tabulated Vapor / Saturation Pressure

− Cavitation mass transfer

− Evaporation-Condensation mass transfer

P-T Table


Optimization


Adjoint Numerics Updates

• Least Squares Cell Based gradient method is available for Adjoint solver– Generally, adjoint sensitivities are more accurate if same gradient method is used for flow and adjoint

solutions

• Spatial and Modal schemes are being deprecated and are removed from the GUI– Dissipation or Residual Minimization schemes are now recommended for all cases

– Spatial and Modal schemes can be accessed in the TUI if needed, but will not be maintained

19.2 2019 R1


Design Tool Usability Enhancements

• Cylindrical Region Creation− Cylindrical Region extents are now configured in a similar

way to Cartesian Regions

− Automatic Coordinate will automatically account for problem setups which include periodicity or MRF zones

• “Get Center” command for scaling and rotation conditions to compute center based on selected surfaces

• Display design constraints and associated geometry

• Preview mesh morphing of selected surfaces

Fluent 2019 R1 Product Updatefrontis.co.kr/wp-content/uploads/2019/05/2019R1-Fluent-1.pdf ·...

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