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-   -   Track after particle hit the wall. (http://www.cfd-online.com/Forums/cfx/124521-track-after-particle-hit-wall.html)

Brigido October 7, 2013 06:52

Track after particle hit the wall.
 
Hi everybody.

I’m doing a steady state simulation with Ansys CFX and using particle transport modeling. I have a problem with the particle track. The track ends a short time before the particle hits an inclined wall (the boundary of the mesh). The wall has a free slip condition.
I want to follow the particle displacement after the impact.

How can I solve this problem?

Thank you!

http://imageshack.us/photo/my-images/809/bpdk.png/

ghorrocks October 7, 2013 17:39

There are many reasons a particle track can terminate - exceed time, distance, integration steps, minimum displacement increment. Have you checked which reason caused this particle track to terminate?

Brigido October 8, 2013 02:59

Thank you for your answer,

I donít know the reason why particle track terminate. In fact, some tracks arrive to the wall and go out across the outlet, and other tracks donít. This last tracks ends a short time before the particle hits the wall.

I realize the track distance varies according to the residuals. If I stop the solver at 1E-3 I can see a short track across the wall. If I stop the solver at 1E-4 or 1E-5, the problem come back.

Thank you again.

Brigido October 8, 2013 04:45

Solved!
The problem was the solver control.

Thanks!

ghorrocks October 8, 2013 05:23

I trust you are not proposing using a very loose residuals convergence critereon is the "solution" to your problem....

Brigido October 8, 2013 05:54

Quote:

Originally Posted by ghorrocks (Post 455649)
I trust you are not proposing using a very loose residuals convergence critereon is the "solution" to your problem....

Of course not. My residual convergence criterion is 1E-5Ö
I changed some parameters of the particle control to solve the problem.

Thanks anyway

ghorrocks October 8, 2013 05:56

I am pleased to hear that, very good.

libbyy October 12, 2013 13:41

Which parameters were causing the termination before reaching the wall?
I am having similar problems in a transient simulation.

Brigido October 15, 2013 09:14

Quote:

Originally Posted by libbyy (Post 456554)
Which parameters were causing the termination before reaching the wall?
I am having similar problems in a transient simulation.

I increased max. tracking time and max. tracking distance at particle termination control.

libbyy October 28, 2013 14:33

I will try that, thanks!


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