# Boundary Condition

1. ### mhmonon

5
Hi all,
I am facing difficulties about boundary condition in Hollow Cylinder. its like wave diffusion equation in hollow cylinder. can anyone help me out to solve this problem. I need some good reverences.
Thank you

2. ### tiny-tim

26,016
Welcome to PF!

Hi mhmonon! Welcome to PF!
We're all very reverend here.

Show us how far you got, and where you're stuck, and then we'll know how to help!

3. ### FredGarvin

5,084
You need to be more precise with what you are doing. That will directly influence what the BCs are.

4. ### mhmonon

5
here I attached the equation with the boundary value.

File size:
11.3 KB
Views:
34
5. ### FredGarvin

5,084
I think your nomenclature is a bit different than what I am used to seeing. You are solving a PDE for the velocity potential, correct? Your boundary conditions are on omega which is usually circular frequency. Is that correct?

6. ### mhmonon

5
actually it is a wave diffusion equation in hollow cylindrical problem.. I think I can solve this problem.

7. ### HallsofIvy

41,050
Staff Emeritus
that is the equation for r, after you have separted variables r and $\theta$. One "unstated" boundary condition is that the function must be finite at r= 0. That gives you one of your constants immediately.

8. ### mhmonon

5
hi HallsofIvy,
Thanks for your reply. Yep you are right. But I am facing here another problem. The problem is that I have no condition at r=0; Instead of r=0 I have another condition that is ri(internal radius)=0. So I can not eliminate one. Bye