Contributions to the theory of sound production by vortexairfoil interaction, with application to vortices with finite axial velocity defect
Abstract
The sound produced when a vorticity field is cut by an airfoil in lowMachnumber flow is analyzed. A general formula is presented for the acoustic pressure when the airfoil is rigid and the chord is acoustically compact. This makes it possible to express the radiation in terms of an integral over the region occupied by the vorciticity; the integrand contains factors describing the effect of the thickness, twist, and camber of the airfoil. Explicit analytical results are obtained for a rectilinear vortex, having small core diameter and finite axial velocity defect, which is cut by a nonlifting airfoil of large aspect ratio.
 Publication:

Proceedings of the Royal Society of London Series A
 Pub Date:
 November 1988
 DOI:
 10.1098/rspa.1988.0122
 Bibcode:
 1988RSPSA.420..157H
 Keywords:

 Aerodynamic Noise;
 Airfoils;
 BladeVortex Interaction;
 Sound Generators;
 Aspect Ratio;
 Green'S Functions;
 Mach Number;
 Acoustics