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-   -   External Aerodynamic Simulation+negative densities (https://www.cfd-online.com/Forums/siemens/56454-external-aerodynamic-simulation-negative-densities.html)

Ramkumar February 18, 2008 03:51

External Aerodynamic Simulation+negative densities
 
Hi all, I would like to know the following queries on STAR-CD:-

1) What boundary conditions on each face of the bounding box need to be given for simulating the aircraft encountering a large side-slip angle simultaneously with angle of attack.

2) When polyhedral cells are created and inviscid option is selected for solving, the solution diverged and the solver reported that the model got negative densities. I didn't understand what is meant by negative densities and why it is reporting like that.

I will be pleased if somebody answers the above questions as soon as possible.

thanks and regards, rvramkumar.

ula February 18, 2008 15:27

Re: External Aerodynamic Simulation+negative densi
 
it means you have bad polyhedral cells in your geometry. Try the same case but with the trimmer model.

Ramkumar February 19, 2008 04:18

Re: External Aerodynamic Simulation+negative densi
 
Thanks. I'll try with trimmer model. Nevertheless, When the mesh is checked, it was not giving any errors. Why this ambiguity?


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