Behavior of intense acoustic noise at large distances

Abstract

Propagation of intense acoustic noise waves is investigated in the case of a nonplanar geometry. It is shown that, at large distances from the source, where the nonlinear effects become negligible, the spectrum of such waves has a universal self-similar shape. The amplitude of the spectrum is determined by a single constant D∞ = D∞(ɛ, R0) (the spectrum steepness at zero-valued argument) whose value depends on two dimensionless parameters: the inverse acoustic Reynolds number ɛ and the dimensionless radius R0. It is shown that the plane of dimensionless parameters (ɛ, R0) can be divided into four regions, so that, within each of them, the quantity D∞ is described by a universal function of these parameters. The numerical factors of these parameters are found from numerical simulations.