Stereoscopic PIV measurements of leading edge separation vortices on a cranked arrow wing

摘要

Three-component velocity measurement results via stereoscopic PIV for leeward flow of a cranked arrow wing with a centre body are presented in order to understand leeward flow phenomena, emphasizing angle-of-attack effects and Reynolds number effects. The tests are conducted in a low-speed wind tunnel with the Reynolds number range from 0.15 × 10{sup}6 to 1.5 × 10{sup}6 at angles of attack of 8° to 20°. Based on instantaneous results, statistical properties such as turbulence kinetic energy are derived. The test results indicate that with increase in angle of attack, interaction between two leading edge separation vortices and a vortex on the body becomes strong, merging into a single vortex. In results on angle of attack effects, vorticity magnitude and kinetic energy have a positive correlation in the cores of the separation vortices. Results of Reynolds number effects show that with increasing Reynolds number, the secondary vortex structure becomes small with the two primary separation vortices moving outward, and the core diameter and vorticity of the vortices become larger and smaller, respectively, due to boundary layer transition on the inboard wing. In general, these Reynolds number effects are similar to the effects of decrease in angle of attack.