Originally posted by Ollie
Wind tunnel test data's validity at low reynolds numbers depends on the accuracy of the test model, the low turbulence level of the tunnel, the instrumentation, etc. I heard Dr. Selig talk at one of the MARCS National Sailplane Symposiums about 1989. He expressed the idea that people who have done wind tunnel testing tend to question the results but, others tend to take the data more seriously than they should.
Can someone explain to the uninitiated (me), whats actually happening behind the scenes in these programs:
Is there generic 'code' available that takes airfoil shape + Re information & spits out resultant polars? If so, is this reliable? What are the limitations?
If the program spits out polars based on actual tunnel tests at measured Re's, smoothed or otherwise, isnt this basically a glorified graphical database? Doesnt this then pose a limitation if you modify an airfoil or request a different Re because it is then forced into some sort of intrepolation routine?