Multiphysics Modeling

in FEMLAB 3

Tuesday, September 14thWoods hole

Remi Magnard

• FEMLAB-overview

• Introduction to the FEMLAB modeling : diffusion-reaction in a zebra fish embryo

• Questions & Demo models on request from audience

Contents

What is FEMLAB used for?

• Structural mechanics

• Heat transfer• Acoustics• Electromagnetics• Fluid Flow• Chemical Engineering• Geophysics• General multiphysics and PDEs

Structure of FEMLAB

• FEMLAB core package– GUI, CAD tools, mesher, solvers, post-processing – Basic physics Modes– Arbitrarily-defined Equations

• Application Specific Modules– Electromagnetics Module

• Statics, eddy currents, microwaves, photonics,…– Structural Mechanics Module

• Solids (including thermal stresses, large deformations, elasto-plasticity, buckling), beams, plates, shells,…

– Chemical Engineering Module• Incompressible NS flow, compressible Euler flow,

chemical reactions,… • electrochemistry, porous media flows,…

Chemical Engineering

Module

Electromagnetics Module

Structural Mechanics Module

Heat Transfer Module

MEMS Module

Earth Science module

Equation implementation within FEMLAB

• Coefficient form:

• General form:

• Weak form:-ux_test*ux-y_test*uy+u_test

fauuuuct

uda

)(

Ft

uda

Diffusion-Reaction in a Zebra Fish Embryo

Introduction

• This model shows the modeling of diffusion-reaction processes in FEMLAB.

• The model shows the possibility of using different properties and different equations in different subdomains.

• The example is originally defined by Sander Kranebarg from the Wageningen University in the Netherlands.

Model Geometry

The geometry consists of three different subdomains:

–Main body

–Yolk

–Surrounding water.

Problem symmetric => only ½ of the geometry modeled

Problem Definition, diffusion

•Diffusion coefficient of the fish embryo : 5e-12

•Diffusion coefficient of the ambient water : 1e-12

•Reaction rate in the main body : -2.5e-4

Boundary condition :• fixed concentration on the exterior boundaries : c=16•Symmetry boundary conditions : 0 cn

Problem Definition, equation implementation

fauuuuct

uda

)(

Coefficient form :

da=alpha=gamma=beta=a=0c = diffusion coefficientf = reaction rate

Boundary condition:

rhu

hgquuuc T )(n

Result, Oxygen partial pressure

Conclusions

• The model is very simple to define and solve in FEMLAB.

• The results agree with the experiments and simulations done by Sander Kranenbarg at the Wageningen University.

• The model can be easily expanded to include effects of convection, which in the model are accounted for by an effective diffusivity.

• Straightforward equation implementation in the GUI

New features in FEMLAB 3.1 (released mid-October)

• Geometry – NURBS supported by IGES import – Live connection to SolidWorks

• Meshing – Support for Quad/Brick/Prism– Structured mesh

• Solvers – 64 bit FEMLAB server on several

platforms – Multigrid preconditioner – Electromagnetics preconditioner

based on multigrid • Structural Mechanics Module

– Piezo application mode – Incompressible materials – Heat-transfer shell

• Electromagnetics Module – Periodic boundary condition for

vector element – Far field postprocessing – 3D hybrid modes for waveguide – S-parameter postprocessing – Maxwell stresses postprocessing – Application mode with 2D quasi-

static formulation – Floating potential – Nonlinear magnetic materials

(example models)

• Chemical Engineering Module – 3D k-epsilon application mode – Divergence free elements

3 New modules!• Heat transfer Module:

– Conduction, convection and radiation modeling– Highly conductive layer boundary condition and heat transfer in shell– Bio-heat equation

• Earth-science module:– Porous media flow in variably saturate substrate– Poroelasticity model– Heat transfer in porous media

• MEMS module:– Piezoelectric material– Microfluidic and micromechanic application : micro-valve model, sensor.

Contact Information:

Jeanette LittmarckRegional Sales Manager

COMSOL, Inc781-273-3322

jeanette@comsol.com

Visit www.comsol.com