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 jinwon park February 12, 2008 17:10

Boundary condition in an axisymmetric 2D flow

As I posted before, I am solving axisymmetric 2D underwater explosion. The 200*200cm domain in r and z coordinates corresponds to the fluid domain consisting of water and explosive gas. The bottom is the rigid wall to obtain the reflecting of strong shock wave.

The initial condition is illustrated by the situation that a half circle with raidus 16cm modeling gas bubble is located at x=0cm y=20cm above the rigid bottom plate. As time goes, high pressure impinges against the rigid bottom and wave is reflected.

I initially set the bottom and the left wall as rigid boundaries. I wonder if such boundary impositions in axisymmetric flows were right. Could anyone advice me how to imply axisymmetric flow motions?

 Ertan Karaismail CFD& February 12, 2008 19:59

Re: Boundary condition in an axisymmetric 2D flow

Is the bottom wall axis of symmetry? If so, I think you should use symmetry boundary condition instead of rigid wall.. Sorry if I got you wrong..

 jinwon park February 12, 2008 20:02

Re: Boundary condition in an axisymmetric 2D flow

Yes. Bottom wall axis is symmetric.If so, what is the symmetric boundary condition?

I set the y-dir velocity at the bottom as zero and the x-dir velocity along the symmetric axis as zero.

Could you give me idea how to define symmetric B.C?

 Ertan Karaismail CFD& February 12, 2008 22:15

Re: Boundary condition in an axisymmetric 2D flow

Taking centerline (x-axis at r=0) as the symmetry axis, you can set du/dr=0 and v=0 on the centerline. But this condition does not imply that symmetry axis is a rigid wall as you said in your first post.

HTH

 dreamchaser July 23, 2012 13:55

how did you create your shockwave??

jinwon park and Ertan Karaismail CFD&AMP ,

I am working on a similar simulation.
I am trying to create an underwater shockwave using a heat source.
I want to see how the shock reflects off of the reflecting walls.

How did you create your shockwave??
I'm using a heat source but I'm not getting any good results.