Mean and Turbulence Measurements in the Near Field of a Wingtip Vortex

Abstract

The rollup of a wingtip vortex, at a Reynoldsnumber based on chord of 4 .6 £ 10 6 , was studied with an emphasis onsuctionsideandverynear-wakemeasurements(upto x/c = 0.678 downstreamofthetrailingedge).Theresearch was conducted in a 32 £ 48 in. (0.81 £ 1.22 m), low-speed wind tunnel. The rectangular half-wing model had a semispan of 36 in. (0.91 m), a chord of 48 in. (1.22 m), and a rounded tip. Seven-hole pressure probe measurements of the velocity ® eld surrounding the wingtip showed that a large axial velocity up to 1.77 U 1 developed in the vortex core. This high a level of core axial velocity has not been measured previously. Triple-wire probes were used to measure all components of the Reynolds stress tensor. It was determined from correlation measurements that