Investigation of Aeroacoustic Noise Generation by Simultaneous Particle Image Velocimetry and Microphone Measurement

Abstract

An experimental investigation involving simultaneous measurements of a flow field and the generated sound is performed. The velocity field around a circular cylinder is measured by Particle Image Velocimetry (PIV) while the radiated sound is recorded with a microphone. Both measurements are conducted in a synchronized manner to enable the calculation of the cross correlation between the flow field and pressure data. The therewith obtained coefficient matrix provides time and space resolved information about the dependency between the flow structures and the pressure fluctuations in the far field in a statistical manner. To improve the signal to noise ratio of the cross correlation function a proper orthogonal decomposition (POD) is applied to the velocity field. The methods seem to be promising to identify flow structures which are correlated with the sources of noise. The developed methods are then applied to the more application related problem of the flow field inside a leading-edge slat-cove.