Suppression of low-frequency pressure pulsations in an open jet wind tunnel by corner vortex generators

Abstract

Suppression of low-frequency pressure pulsations using vortex generators at the jet nozzle is investigated for a large low-speed open jet wind tunnel. The pressure pulsations are measured for different arrangements of the vortex generators at the jet nozzle. It is found that only generators installed at the corners of the nozzle can reduce low-frequency pressure pulsations and generators installed in the middle parts of the four inner walls of the nozzle not only fail to decrease the pulsations but also excite them outside the jet even more strongly. On the basis of these results, corner vortex generators (CVGs) are adopted for control of low-frequency pressure pulsations in the open jet wind tunnel. After installation of CVGs, both the amplitude of pressure pulsations in the plenum and the turbulence intensity at the center of the test section are significantly reduced.