# Cp Correction for wind tunnel model

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 April 16, 2003, 17:35 Cp Correction for wind tunnel model #1 Rodge Guest   Posts: n/a Hello, I'm doing some work in CFD-experimental flow over different models. I started with a cilinder and got good results but the Cp in the leading edge is higher than one. Since Fluent calculates Cp with the reference values of P,V and density I have a problem because there is a great blockage and the flow speeds up around 30% of the reference speed. So my question is: What is the right speed to use in this case? I know everybody who has done something like this has the same problem so I hope one of you people can tell me the "Right way" Thanks

 April 17, 2003, 06:38 Re: Cp Correction for wind tunnel model #2 Mario Guest   Posts: n/a Maybe I have not understood properly your problem, but If you're simulating a cylinder (Extended stagnation region), my Opinion is that there's nothing strange having Cp greater than one at the stagnation ("leading") point, for there the flow stops and dynamic pressure should be converted to static (negleting viscosity effects)... What do you think about it? Hope this could help, just let me know, Mario.

 April 17, 2003, 09:18 Re: Cp Correction for wind tunnel model #3 Rodge Guest   Posts: n/a Yes, you are right about the dynamic/static pressure change, but should I use the reference speed? or the real speed at that point?

 April 30, 2003, 09:07 Re: Cp Correction for wind tunnel model #4 Bob Guest   Posts: n/a In the wind tunnel don't they use the reference speed ? if thats the case I guess you should use the same for your comparison ? bob

 April 30, 2003, 09:51 Re: Cp Correction for wind tunnel model #5 Rodge Guest   Posts: n/a Thanks Bob, I just realized how dumb my question was.

 May 1, 2003, 09:00 Re: Cp Correction for wind tunnel model #6 Bob Guest   Posts: n/a No Not dumb, we all have our moments. I think its cool how people can ask any question on hear and not worry that the question may be simple or comple. Bob