Expert: Paul Soderman - 11/14/2010

Question
Dear Paul,

I am doing a project on designing a closed circuit wind tunnel with open working section. My test section size is 0.5 m Diameter by 1 m wide. I need to come up with required power for producing 15m/s flow speed on working section. Could you please help me up pointing to the right direction.

thanks,
Dunil  

Answer
Dunil
The power output required by the wind tunnel fan is equal to the sum of the flow power losses in each section of the wind tunnel.  The following reference lists the basic equations and losses for typical wind tunnel components including an open jet test section, turning vanes, etc. in the Appendices:

Soderman, P.T. and Olson, L.E.:  Large-Scale Aeroacoustic Research Feasibility and Conceptual Design of Test-Section Inserts for the Ames 80-by120-Foot Wind Tunnel.  NASA TP 3020, Dec 1990.  

This is primarily for a non-return wind tunnel but you can ignore the inlet and exhaust losses.  You can also get the following report that covers closed-return wind tunnels.

Eckert, W.T.; Mort K.W.; Jope, J.:  Aerodynamic Design Guidelines and Computer Program for Estimation of Subsonic Wind Tunnel Performance.  NASA TN D-8243, Oct 1976.

You can also find good information on losses in:

Blevins, R.D.:  Applied Fluid Dynamic Handbook.  Van Norstrand Reinhold Co. 1984.

I believe NASA had digitized those reports and put them in pdf files you can download. Do a google search on the report numbers and you will find the NASA distribution center.  Good luck.
Paul