Metrics That Characterize Nonlinearity in Jet Noise

Analyses of acoustic data recorded during a series of high thrust military jet flyovers indicate that the skewness of the pressure is not well correlated with the sound pressure level, but the skewness of the gradient is. The influence of propagation distance and engine exhaust velocity on the results requires further examination. The results presented here emphasize the need for high bandwidth, high signal to noise ratio measurements. [Work supported by the Strategic Environmental Research and Development Program.]