Pressure fluctuations generated by uniform distortion of homogeneous turbulence

The behavior of homogeneous turbulence subjected to uniform distortion is investigated. The problem is solved in a linear formulation that allows for the effect of the inertial interaction between the mean flow and turbulent velocity fluctuations. Although it is linear and easily taken into account, the viscous term in the equations is discarded; this action is valid if the distortion rate is somewhat higher than the turbulent-energy dissipation rate. Properties of acoustic pressure fluctuations during spherical and axisymmetric distortion are analyzed. It is shown that the interaction between eddy turbulence and the mean velocity field may lead to the emergence of a significant acoustic mode. It is noted that the results obtained may be used to calculate the acoustic radiation generated by turbulence subjected to rapid distortion.