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-   -   Ansys CFX Atmospheric Boundary Layer (http://www.cfd-online.com/Forums/cfx/26743-ansys-cfx-atmospheric-boundary-layer.html)

Marco December 1, 2008 10:13

Ansys CFX Atmospheric Boundary Layer
 
Hi guys, I have a problem with a simulation in Ansys CFX. I have a big domain (about 500 x 100 x 1000m), logarithmic velocity profile in inflow, roughness on the ground and nothing else. But my simulation doesn´t work if reynolds number are higher then almost 10e8. This is quite strange because reynolds number shouldn´t be a problem for Ansys. Do you have any suggestion where is my problem?

thanks a lot

Marco

Glenn Horrocks December 1, 2008 21:46

Re: Ansys CFX Atmospheric Boundary Layer
 
Hi,

The problem in very high Re flow is almost always transient structures causing a steady state simulation to diverge. I am not sure how to get these flow to converge as steady state (any ideas anyone? I have tried this briefly but failed so far), so the best thing I can recommend is to run transient and resolve the transients. Also check to see whether the transient features are significant.

Glenn Horrocks


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