Wall-pressure fluctuations measurement using microphone array - Correlation analysis of coherent structure in backward-facing step flow

Abstract

The measurement of wall-pressure-fluctuations of turbulent flows using microphone array was introduced. Simultaneous measurements of wall-pressure-fluctuations of turbulent separated and reattaching flow over a backward-facing step were performed using 30 microphones. The comparative analysis using auto-spectrum and wall-pressure-fluctuations coefficients demonstrates that the flow is characterized by low-frequency motions of large-scale vertical structures. Spatial scale and convection velocity of low-frequency coherent vortical structures embedded in the turbulent flow were revealed in terms of auto- and cross-correlation analysis of low-pass filtered wall-pressure-fluctuations.