Aeroacoustic Measurement with Combined Proper Orthogonal Decomposition Analysis

In this study, a technique was developed to analyze the relation between flow structures and the emitted sound pressure using proper orthogonal decomposition and linear stochastic estimation; experiments were conducted to examine the technique's feasibility. Data obtained by simultaneous measurement of the velocity field in the wake of a circular cylinder and far field sound pressure emitted by it were analyzed by present technique. The results showed that the emitted peak sound pressure was strongly related to the first mode of the velocity field in the wake near the cylinder with a pair of fluid lumps having positive and negative streamwise velocity fluctuations on opposite sides of the centerline of the wake. Therefore, this complementary technique may be useful for detecting the flow structure related to the sound emission.