Experimental study of the influence of the plate temperature on the aeroacoustic field for a jet impinging on a slotted plate

Impinging jets are developing widely in the industry because of its substantial uses in many industrial applications and specifically cooling purposes. However, jets impinging on slotted surfaces can produce under certain conditions high noise, leading to acoustic nuisance. Aero-acoustics in impinging jets have been under investigations and studies experimentally and numerically for many years. However, only few studies were carried on in order to investigate the influence of plate temperature on noise emission. In this paper, the correlation between the acoustic production and the plate temperature has been studied. The experiments are carried out for two Reynolds numbers, Re = 3550 representing a peak in sound pressure levels and Re = 3750 representing a drop in sound pressure levels, at an impact distance L=4 cm. Acoustic, Thermal, and velocimetric measurements were done using four different microphones, two infrared cameras, and PIV technique, respectively. Measurements were done simultaneously in order to correlate the phenomenon. Results showed significant variations in the sound pressure levels for the second Reynolds number. However, no variation was detected for the first Reynolds number.