An experimental investigation has been conducted to determine the physical process of the noise production from the trailing edge of an isolated two-dimensional airfoil embedded in a low turbulence uniform mean flow. The Reynolds numer of the airfoil based on chord was greater than 106 and that the boundary layer was fully turbulent at the trailing edge. Smoke injection technique and spark shadowgraphy were used to study the structural features of the boundary layer. Two point joint statistical analyses were made on the surface pressure, the radiated sound and the relationship between the two quantities. Operating conditions included two free stream velocities and two angles of attack for both a naturally developed and an artificially tripped boundary layer. Flow visualizations revealed the existence of large scale coherent motions in the outer region of the boundary layer. The observed coherent motions had scales of the order of boundary layer thickness and a convection velocity near the free stream velocity. (DePo)
On sound radiation from the trailing edge of an isolated airfoil in a uniform flow
Ueber die Ausstrahlung von Schall an der Hinterkante eines isolierten Tragfluegels in einer gleichmaessigen Stroemung
AIAA-Papers ; 1-17
1979
17 Seiten, 32 Bilder, 1 Tabelle, 24 Quellen
Aufsatz (Konferenz)
Englisch
Divergent-trailing-edge airfoil flow
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