PROPAGATION OF FINITE-AMPLITUDE SOUND THROUGH TURBULENCE - A GEOMETRIC ACOUSTICS APPROACH

A propagation model is reported that describes the nonlinear propagati on of sound through turbulence in the geometric acoustics limits. Indi vidual realizations of a two-dimensional Gaussian correlated turbulent field are generated. Linear geometric acoustics is used to trace the rays through each realization of the turbulent field. A nonlinear tran sport equation is derived that describes the propagation of the sound along the eigenrays that connect source and receiver. The equation is solved by a Pestorius type algorithm. It is shown that the equivalent nonlinear distorsion after propagation through turbulence is always le ss than that for the homogeneous case. The effect is more pronounced f or random velocity fields than for temperature fields. Results from a numerical experiment that simulates the propagation of spark-produced plane N waves through turbulence me presented. When the turbulence res ults are compared with the no-turbulence data, it is observed that tur bulence decreases on average the peak pressure of the N waves and incr eases the rise time. These observations confirm the results from the m odel experiment (Lipkens, 1993) in which spark-produced N waves are us ed to simulate sonic boom propagation through a turbulent atmosphere.