Set these boundary conditions in COMSOL 3.4?

In summary, the conversation is about using COMSOL for solving PDEs in cylindrical coordinates and implementing boundary conditions. The discussants also mention using COMSOL for photonic crystal fibers and tapered optical fibers, and ask for resources and tips on how to create these structures in COMSOL.
  • #1
sunilpatilher
1
0
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 anyone tell me how to set these boundary conditions in COMSOL 3.4?

Thanks again.
sunil
 
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  • #2


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
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


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


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 don't 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
 

1. What is the purpose of setting boundary conditions in COMSOL 3.4?

The purpose of setting boundary conditions in COMSOL 3.4 is to define the behavior of the model at the boundaries. This helps to accurately simulate real-world conditions and obtain meaningful results.

2. How do I set boundary conditions in COMSOL 3.4?

To set boundary conditions in COMSOL 3.4, you can use the Boundary Settings window. This can be accessed by right-clicking on the boundary in the model tree or by selecting the boundary in the graphics window and clicking on the Boundaries button in the ribbon.

3. What types of boundary conditions can be set in COMSOL 3.4?

COMSOL 3.4 allows for a wide range of boundary conditions to be set, including fixed value, prescribed flux, symmetry, periodic, and more. Each type of boundary condition has its own specific purpose and can be selected based on the needs of the model.

4. Can I set different boundary conditions for different boundaries in COMSOL 3.4?

Yes, it is possible to set different boundary conditions for different boundaries in COMSOL 3.4. This allows for a more accurate and realistic simulation of the model, as different boundaries may have different behaviors in real-world scenarios.

5. How do I know if I have set the correct boundary conditions in COMSOL 3.4?

The best way to ensure that the correct boundary conditions have been set in COMSOL 3.4 is to carefully review the model and its boundaries, and to run test simulations to compare the results with expected outcomes. You can also consult the COMSOL documentation or seek assistance from experienced users for guidance on setting appropriate boundary conditions.

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