On the correlation of the acoustic signal of microphones mounted on a flat plate to the turbulence of an impinging jet

Abstract

An axial symmetric fan driven by a brushless actuator with variable frequency is used to generate a turbulent circular jet leading to typical core‐velocities of around 10 m/s (Re = 99000). The jet impinges on a flat plate. Turbulence is generated using different sets of turbulence generators in the pipe consisting of meshes, rods, cubes and spikes. The turbulent flow field downstream of the pipe outlet is measured using two‐axis hot wire anemometry with a temporal resolution of a minimum of 48 kHz. The CTA probe is positioned using an automated three‐axis traversing system. 12 Microphones are mounted on a flat plate and are used to capture the wall pressure fluctuations. CFD calculations are performed for the different turbulence generators and are compared to the acoustic and CTA signals. An important aspect of the work is the simultaneous recording of both the CTA‐ and the acoustic signals in the experimental and numerical approach. This allows for the calculation of correlation patterns between turbulence and the acoustic signals of the plate mounted microphones.

Publication
Journal of the Acoustical Society of America, Vol. 123, Issue 5
Date
Links