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-   -   Proper Wind Tunnel Inlet BC for Fans and Other Streamwise Flow Acceleration Devices (http://www.cfd-online.com/Forums/main/103383-proper-wind-tunnel-inlet-bc-fans-other-streamwise-flow-acceleration-devices.html)

lordvon June 19, 2012 00:45

Proper Wind Tunnel Inlet BC for Fans and Other Streamwise Flow Acceleration Devices
 
Hello everyone,

I was wondering what would be the proper inlet boundary condition to mimic a wind tunnel in the case of a propeller or similar device in the test section that accelerates the flow in the streamwise direction.

If we simply use a fixed velocity inlet then unphysical results may occur, since in a real wind tunnel the fixed velocity inlet would not be enforced so rigidly.

Would a total pressure condition be sufficient?

JBeilke June 19, 2012 01:42

The "correct" way to deal with this is to simulate the wind tunnel before and take the flow values (velocity, turbulence, temperature) from the inletsection as input values.

Otherwise do a good measurement of the values.

Far June 19, 2012 11:29

You can find all details in this paper (I am one of the authors)

Masud, J., and Ahmed, S. "Design Refinement and Performance Analysis of Two-Stage Fan for Small Turbofan Engines", Paper # AIAA-2007-23, 45th AIAA Aerospace Sciences Meeting and Exhibit at Reno, Nevada, USA (2007)


http://pdf.aiaa.org/preview/CDReadyM.../PV2007_23.pdf

lordvon June 27, 2012 12:17

I think I will just go with the openfoam BC of totalPressure (atmospheric + dynamic pressures) for the inlet, and atmospheric pressure for the outlet.

akiss20 June 27, 2012 12:54

Quote:

Originally Posted by lordvon (Post 368601)
I think I will just go with the openfoam BC of totalPressure (atmospheric + dynamic pressures) for the inlet, and atmospheric pressure for the outlet.

Is your tunnel a closed system? If so, the pressure boundary condition for the outlet may not be valid.

My 2 cents


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