EXPERIMENTAL STUDY ON CHARACTERISTICS OF PRESSURE FLUCTUATIONS OF LONGITUDINAL VORTEX SYSTEM GENERATED AROUND THE LEADING EDGE OF A DELTA WING

Abstract

Longitudinal vortex is generated behind the front-pillar of automobiles. The vortex induces strong aerodynamic noise at high speed cruising. To investigate generation mechanism of aerodynamic noise, the vortex was reproduced by the delta wing whose attack angle of 15 degrees was merged in the uniform flow at 10, 20, 30m/s. Time derivative of wing surface pressure fluctuations regarded as aerodynamic noise source were measured in the low noise wind tunnel. Consequently, it was found that higher frequency of 3 kHz was largest close to the tip of the vortex, and the lower 500 Hz peaked at the rear.