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mach000 April 1, 2010 10:43

wallscale bulk
Hi to everybody,
i'm studying a multiphase problem.
During the simulation I have some informations about "wallscale bulk".

There is someone that could explain me the meaning of this parameters and how I can understand if it's all ok?

Thank you very much in advance

ghorrocks April 2, 2010 06:10

This is the solver working out the distance to walls for the SST turbulence model. As long as it converges a bit it should be fine. It is a very numerically stable solver (and simple mathematics) so rarely causes a problem.

mach000 April 2, 2010 06:46

thank you for your reply.

The problem is that at the beginning of the simulation I have "Failure" about wallscale bulk and consquently I have overflow.

It looks that with double precision simulation the run goes better...

ghorrocks April 2, 2010 07:02

This is quite rare, and yes, sometimes switching to double precision can fix it. Hopefully you are proud to have found such an unusual problem.

There are some settings which control it, I have never used them but I know they are there. You might be able to fiddle with the wallscale convergence factors and get it to converge without resorting to a double precision solver.

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