This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Similarity in Wind Tunnel Testing In terms of non-dimensional force and moment coefficients, these depend on numerous non-dimensional input parameters. ,......) Re, , ( ,......) Re, , ( = = M C C M C C D D L L In many aerodynamic applications, ) Re, , ( ) Re, , ( = = M C C M C C D D L L So, to match flight condition D L C C & in an experiment, we should match flight . Re, , and M Matching is relatively easy How about simultaneous Re & M matching? = = L V a V M Re Consider the Wright Brothers Wind Tunnel: a is the atmospheric speed of sound at ground level to good approximation = = a a V V M M T T T For altitudes from 0-30k ft., a varies by only about ~15%. ! V V T Since Wright Brothers Wind Tunnel is limited to about mph 200 < T V , we cant match M unless it is low....
View Full Document