Experimental study of the vortex organization in a rectangular impinging jet in the presence of self-sustained tones

Abstract

Impinging jets could be used in the terminal elements of ventilation systems to ensure a better air mixing in the residential buildings. However, under certain configurations, these jets could be accompanied by a whistling tone. This whistling tone is amplified when the jet encounters a slotted obstacle in its flow. Usually, for a given Reynolds number, these tones are characterized by a single frequency. In this study, we represent the jet behavior for a Reynolds number Re=5900 where two different frequencies are obtained in the spectrum of the whistling tone signal. This unusual aspect is related to an altered vortex organization as we will show using Stereoscopic PIV (SPIV) measurements.

Keywords

• Impinging jet
• Vortex
• Self-sustaining tones
• Stereoscopic PIV (SPIV)