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-   -   Drag & Moment Coeff and Pressure (http://www.cfd-online.com/Forums/cfx/20088-drag-moment-coeff-pressure.html)

ogbeni January 8, 2004 07:44

Drag & Moment Coeff and Pressure
 
Hello I am doing a simulation on a bluff body, from my results file, I am able to calculate the drag coefficient fine, but the lift and Moment coefficients confuses me, can any one please expalain how to from my CFX5 output. I also wanted to obtain pressure profiles on the body, I set inlet pressure to 10e+5 and outlet to zero, but the pressure profiles looks wrong, how should I have set it up ? Thanks

Louwrens January 12, 2004 08:30

Re: Drag & Moment Coeff and Pressure
 
Easiest way is probably to calculate the lift and moment directly in Post, and then work out the coefficients yourself...

If your pressure profiles look wrong, are you sure you set your model up correctly (ie have enough "free space" around the body that pressure waves propagating upstream and to the sides will not be influenced by the boundary conditions), are your grid fine enough, are you resolving your boundary layer adequately, are you using a second-order advection scheme if you've got a tet mesh...

I know these are elementary questions, but maybe you missed something. Also, I'd rather use a velocity inlet than a pressure inlet, if its possible in your application.

Good luck

Louwrens


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