News in COMSOL Multiphysics 3.2

PlacePrague

2005-11-15

Bertil Waldén

COMSOL AB

FEMLAB is now COMSOL MultiphysicsTM

• First name was PDE Toolbox– Because it solved PDEs

• Second name was FEMLAB– Because it made use of the Finite Element Method

• Now we are dealing with Multiphysics and want a name that expresses this

• Name structure – same product and company name– Not all future products will be FEM or FEA based

COMSOL Products

New Products

• COMSOL ScriptTM

• CAD Import Module

• Add-ons to the CAD Import Module– Pro/E Import Module– CATIA V4 Import Module– CATIA V5 Import Module– Inventor Import Module– VDA-FS Import Module

COMSOL ScriptTM

Command-line modeling, technical computing, visualization and GUI-design

Programming language and fast graphics

COMSOL Script:• Fully compatible with the MATLAB language

– All data types except objects– Command line debugger, dbstop, dbstep, dbcont, ...– Java interface

• Fast 3D graphics using OpenGL acceleration (50 times faster than Matlab)

Batch execution with COMSOL Script

• Requested feature that allow several simulations to run sequentially or simultaneously

• The simulation can be distributed over a network to run on different machines

• COMSOL Script executes an M-file that defines the simulation

Main news in COMSOL Multiphysics 3.2

Support for units

• Metric units– SI units – CGS units– MPa units suitable

for structural analys– EM units– ES units

• English units– British engineering

units– FPS– IPS– Gravitational IPS

• No units

Pre-defined multiphysics couplings

Grouping of subdomains and boundaries

More improvements

For constants and expressions:• save and open • add descriptive comments

• Customized report

Select the content of your report

New material library functionality

• Support for anisotropic materials and orthotropic materials – Both the 6-by-6 elasticity matrix in 3D and the 4-by-4

elasticity matrix in 2D are supported.

• Support for piezoelectric materials– The piezoelectric matrices: elasticity matrix, coupling

matrix and permittivity matrix are supported.

• Support for elastic-plastic and hyperelastic materials• Material functions can be specified

– For example: temperature dependent material properties

• Further develop the solvers to solve MUCH larger problems MUCH MUCH faster– Built-in support for wave equations (DOFs reduced with 50%,

iterative solvers more efficient)– 5-10 times larger CFD problems solved with new multigrid

smoother (Vanka) for laminar flow (tested), turbulent flow (tested), arbitrary multiphysics problems (not tested)

– A bunch of under-the-hood improvements on mesh stability, incomplete LU preconditioner, file storage of solutions (during transient solving)

Performance Improvements:

Wave Equations in 3.1 and 3.2:

• 3.1: Substitution– Unsymmetric Jacobian matrix with

zeros on the diagonal– Not good for iterative solvers– Memory waste– Two dofs to keep track of

• 3.2: New formulation– One variable, symmetric Jacobian if

the PDE is – Very good for iterative solvers!

– Memory efficient!

0

a

vd c u f

tuv

t

fuct

ud

t

ue aa

2

2

Transient analysis improvements

• Time derivatives can be used freely in expressions:– Logical names: ut, utt, uxt, uxtt– Reduces the number of degrees of freedom in your models.– Memory and solution times significantly improved.– Store solution on file.

New ODE Interface

• Type in ODE as it is: ut-u=0• Creates a global DOF• Easier to use than Weak Form,

Point

New CFD Benchmark: Turek's

• Laminar flow, 3D• On 32-bit architecture, 2GB RAM: 450 kdofs, 60-90

minutes– In 3.1, 240 kdofs, 4-5 hours

• On 64-bit architecture, 12 GB RAM: 2150 kdofs, 6-8 hours– In 3.1, 400-500 kdofs, 16 hours

Exciting new feature: Moving boundaries and mesh with the ALE-method

Moving meshes with ALE• ALE is a technique used to handle single physics or multiphysics problems

where the effect of the deformation on the physics cannot be neglected. • A simple example of this is the 2D fluid structure interaction model:

Original mesh Deformed mesh

• ALE smooths out the mesh deformations in the entire domain in a diffusive manner

• Analogy: Think of the mesh element edges as interconnected springs which are compressed or extended due to prescribed deformations on the boundary or in the subdomain

Moving meshes with ALE

Sloshing tank

Peristaltic pump

ALE method - limitations• Does not handle topology changes

OK

Not OK

Example: Parameterized geomety (ALE)

Objective

• To make it possible to automate modification of geometry without resorting to command line

• The changes made to the geometry can be for example translation or scaling of a given geometry object

Simple example of Parameterized Geometry

Distributed heat source

All boundares kept at T=288 K

Moving drilled hole (mesh deformation)

Results, tempDeformed mesh

• ”Catch” parts of COMSOL Multiphysics in your own easy-to-use windows.

• Create a GUI of your own that can run all types of scripts: COMSOL Multiphysics or user-defined.

• Uniqe function: customized GUIs work with all types user functions for all types of analysis!

New in COMSOL 3.2: Customized GUIs

How to do?

Two simple steps:

1. Create a Java component through a simple script

2. Run your own script functions through a GUI event (push a button)

Why customized GUIs?

• Perfect for teaching.• Allow the user to generate simplified GUI for

customized problem.• Non specialist engineer can do a finite element

analysis.• Consultancy company that can provide a study to

their own customer.• Design engineer that are not specialized in FE

analysis for quick and common optimization of designed.

Components• Each frame can be split in different panel.

• Don’t need to define the size of each panel as they are automatically scaled on a grid

Panel 2

Panel 1

Panel 3

Panel 4

Axes

The m-files

minigui.m (sets up the GUI):f1=frame('FEMLAB','size',[800 600]);

p1=panel;

p1.add(label('Rectangle width:'),1,1);

p1.add(label('Rectangle height:'),2,1);

p1.add(label('Circle center x:'),3,1);

etc.

p2=panel;

p2.add(label('Element size:'),1,1);

etc.

f1.get('geombutton').addActionListener('geommodel');

f1.get('meshbutton').addActionListener('meshmodel');

f1.get('solvebutton').addActionListener('solvemodel');

f1.get('plotbutton').addActionListener('plotmodel');

geommodel.m

(creates the geometry):function geommodel(event)

width=frame.get('width').getValue;

height=frame.get('height').getValue;

centerx=frame.get('centerx').getValue;

centery=frame.get('centery').getValue;

radius=frame.get('radius').getValue;

g1=rect2(width,height,'pos',{'0','0'});

g2=circ2(radius,'pos',{centerx,centery});

s.objs={g1,g2};

fem.draw=struct('s',s);

fem.geom=geomcsg(fem);

geomplot(fem);

Quick preview: COMSOL Reaction Engineering LAB

What is the Reaction Engineering Lab?

3 cornerstones of Reaction Engineering

• Reaction kinetics– Evaluate it quickly

• Physical properties of reacting systems– Be accurate

• Modeling coupled phenomena– Stay organized

Setting up reaction kinetics

Physical properties of reacting systems