# Proper Wind Tunnel Inlet BC for Fans and Other Streamwise Flow Acceleration Devices

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 June 19, 2012, 00:45 Proper Wind Tunnel Inlet BC for Fans and Other Streamwise Flow Acceleration Devices #1 Senior Member   Robert Join Date: Sep 2010 Posts: 154 Rep Power: 6 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?

 June 19, 2012, 01:42 #2 Senior Member   Joern Beilke Join Date: Mar 2009 Location: Dresden Posts: 185 Rep Power: 9 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.

 June 19, 2012, 11:29 #3 Super Moderator     Sijal Ahmed Memon (turboenginner@gmail.com) Join Date: Mar 2009 Location: Islamabad Pakistan Posts: 3,914 Blog Entries: 6 Rep Power: 38 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

 June 27, 2012, 12:17 #4 Senior Member   Robert Join Date: Sep 2010 Posts: 154 Rep Power: 6 I think I will just go with the openfoam BC of totalPressure (atmospheric + dynamic pressures) for the inlet, and atmospheric pressure for the outlet.

June 27, 2012, 12:54
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Andras
Join Date: Aug 2011
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Quote:
 Originally Posted by lordvon 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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