-Nan- error
 

Hi all, I am simulating a case with thermal radiation, velocity and pressure BCs, High Re turbulence model. The case is transient. Model contains hexa, piramid, tetra elements. My run is coming out with -Nan at TKE and dissipation residuals. I tried giving steady state results as initial guess but still it fails. My PISO correctors are not exceeding the 20 limit. What could be the reason? Thanks in advance.

Re: -Nan- error
 

Turbulence values at boundaries?

Re: -Nan- error
 

Thanks roadracer. But how to see where it is giving error? Is case.div useful? thanks again.

Re: -Nan- error
 

The .div file is very useful: just post-process it like a .pst file. This will hopefully show you where the problem lies in the domain. The NaNs suggest there is maybe a division-by-zero or something like that in the code. Something the STAR developers didn't expect to be zero - as roadracer said, turbulence at boundaries could be one thing. Also initial conditions for turbulence.

Re: -Nan- error
 

You might also want to check if there is a zero edge length in one of your cells.

NAN's are hard to find, good luck.

Re: -Nan- error
 

HI, I have successfully run the steady state case on the same mesh and I think there is no problem in the mesh. problem is occuring only in transient case. I am looking at the initial condition of the turbulence or its location. Thanks,

Re: -Nan- error
 

I tried a lot to start the run but failed. Actually I don't want to simulate transient flow(velocity), but only variation of temperature with time. Velocity being constant with time. How to do that? If I give velocity BC by nrmal way, it simulates the velocity also with reapect to time. Kindly help.