Trailing Vortex Wind-Tunnel Diagnostics with a Laser Velocimeter

A two-dimensiona l laser velocimeter whose focal volume can be rapidly traversed through a flowfield has been used to overcome the problem introduced by excursions of the central vortex filament within a wind-tunnel test section. The operation of the instrument is reviewed and data are presented which accurately define the trailing vortex from a square-tipped rectangular wing. Measured axial and tangential velocity distributions are given, both with and without a vortex dissipator panel installed. From the experimental data, circulation and vorticity distributions are obtained and the effect of turbulence injection into the vortex structure is discussed. Nomenclature wing span wing chord lift coefficient radial coordinate from vortex center wind-tunnel mainstream velocity axial velocity component tangential velocity component maximum tangential velocity stream wise ordinate, aft from trailing edge normal ordinate, above upper wing surface from trailing edge normal location of vortex center angle of attack, deg slope of velocity distribution in core region vorticity