PIV Measurements of Aeroacoustic Sources of a Shallow Cavity in a Pipeline

The aeroacoustic sources generated by flow over a cylindrical shallow cavity in a pipeline are examined in the presence of plane sound waves at various Strouhal numbers and sound intensities. The cavity is exposed to high Reynolds number fully developed turbulent flow. Extensive PIV flow measurements are performed to characterize the unsteady velocity and vorticity fields at various time instants within the sound cycle. Finite element analysis is used to obtain the particle velocity field of the sound field. The results of the PIV flow measurements and those of the finite element simulations are combined into Howe’s aeroacoustic integrand to compute the spatial and temporal distributions of the aeroacoustic sources resulting from the cavity shear layer interaction with the sound field. The results are compared with the measured aeroacoustic source strength obtained by means of the Sound Wave Method (SWM) [1]. The advantages and disadvantages of both techniques are discussed.