# COMSOL help

1. Jan 4, 2008

### gganendra

Hi everybody, newbie here...

im doing a modelling work with comsol and have a problem of solving using navier-stoke equation for the boundary. is it possible to discretize the boundary condition into several parts and apply different condition in each segment?

thank you beforehand,

2. Jan 4, 2008

### mda

I have never tried NS but I am familiar with the COMSOL environment.
You can definitely apply different BC to different physical boundaries.
Reading between the lines I take it that you have a smooth boundary that you wish to divide?
This is done at the drawing stage, e.g. if you have a rectangular plane you can divide it using lines.

I'm curious about your reasons for doing this... normally if this was part of your problem specification you would have done this at the beginning.

3. Jan 5, 2008

### gganendra

thank you, i am doing modelling of biofilm growth on a rough surface which is influenced by hydrodynamic stress. I am using comsol 3.3 script, it is more comfortable than using comsol multiphysics

thank you

4. Feb 21, 2009

### rr00053

Hi everyone... i am new user of COMSOL multiphysics... I have to model the heat transfer between an electromeagnetic wave and solid material.... ie i have to get a model to explain hw an em wave is used to heat up a material...can anyone help me in doin this....

5. Feb 21, 2009

### Gokul43201

Staff Emeritus
Please describe the experimental setup completely.

6. Feb 21, 2009

### rr00053

Hi gokul...actually i want to model the energy coupling between a electromagnetic source and solid material...

7. Feb 21, 2009

### rr00053

that is , i have to model how a solid material is heated using any em source....for instance any infra red source (any light bulb) is used to heat a material say Silicon... how can i model the heat transfer from the bulb to silicon and then i have to plot the temperature variation vs time...
i tried heating the material with a heating element specified in comsol library and tat seems working...but nw i have to replace tat solid heating element by a electromagnetic source...
can u pls help me

8. Feb 21, 2009

### Gokul43201

Staff Emeritus
I'll have to look. I don't recall seeing a module that can do this, but I may be wrong.

9. Feb 21, 2009

### rr00053

@ gokul...ya even i didnt see any model to do this...but if you go to comsol.com website and see for the heat transfer models in the model gallery there is an example which they have mentioned...its about thermal annealing of silicon waffer using indirect IR lamp...but unfortunatly we dont have access for any further info on that...
so i think it is possible to do model my problem...but i have no idea hw to do...is it in PDE application mode???
pls reply if u find out any info on my model...

10. Mar 26, 2009

### P_Andrei

Hello everybody
I have a problem with Comsol 3.4 installation, it doesn't run after the installation is finished.
I get the following COMSOL Error: "No class com/femlab/gui/Femlab on classpath."
I've tried to uninstall but also unsuccessful, I get the message:"EXIT FAILURE: Failed to load uninstallation components." and "Can't find comsol.opts file".
The question is whether there is a solution to uninstall the program and where the comsol.opts file has to be placed so it could be found during the uninstallation (I have the file but I don't know the directory where it should be placed)