Set these boundary conditions in COMSOL 3.4?

  • #1

Main Question or Discussion Point

Hello friends,
Thanks in advance for your answers,

I am using genreal form of PDE to solve system of PDEs. I am dealing with cyllindrical co-ordinates under axisymmetric case. I am not able to understand how to implement boundary conditions such as,

DEL. Gamma=F is system of PDEs
where Gamma is function of (u, v, ur, uz,vr,vz..)

I would like to set u=0 and vr=0 on one of boundary, vr stands for derivative of v w.r.t. r.

can any one tell me how to set these boundary conditions in COMSOL 3.4?

Thanks again.
sunil
 

Answers and Replies

  • #2
PerennialII
Science Advisor
Gold Member
898
0


You can give Dirichlet, Neumann or mixed BCs directly from physics --> boundary (depending on your application mode), or then you can go about it via physics --> equation systems and work with the boundary terms for the PDE you're working with or define something specific for a boundary in question (if you need something more general). If you've something beyond this there are further means, Comsol is fairly general this way.
 
  • #3
5
0
PCFs and COMSOL

Hello everyone, I am trying to understand COMSOL 3.5 and I am interested in Photonic crystal fibres and tapered optical fibres. First of all, could you please tell me what is the background of the layout? When you create a design/object, the rest area is air or I need to define another object as the environment?
Now, could you please tell me where I can find instructions of how creating a PCF structure in COMSOL? Furthermore, do you know any good notes/books for COMSOL for photonic applications??
Thank you in advance

Chris
 
  • #4
3
0


Chris,

Did you check out the models and documentation that comsol provides? They have some examples that once the work through may be helpful. I think it has an optical fiber example in there. That's pretty much how I have taught myself Comsol. I don't know of any good books that are out and I have looked around. Maybe someone else knows of one?

Jacob
 
  • #5
5
0


Dear Jacob,
Thank you for your reply. Of course I have checked the examples and the one with the optical fibre; however an optical fibre is a very simple structure and quite different from a photonic crystal fibre and a tapered fibre (of diameter 1um without cladding). Furthermore, due to fact that these models are ready, I dont really know every parameter used in the model because its default and unfortunately the documentation does not explain in details. Thank you for your reply and your time, though. I hope that someone else is also faced with similar problems and will give an answer.

Best Regards,
Chris
 

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