A Exact Model for Linear Acoustical Scattering from Atmospheric Turbulence.
Abstract
Most of the current approximate acoustic wave equations apply for ambient conditions (turbulence) in which the scale length a of the spatial variation of the ambient temperature and flow velocity is much larger than the acoustical wavelength lambda; this is not the case in many applications of interest. An alternative set of coupled acoustical wave equations, valid for any {aoverlambda}, is derived from first principles. These equations involve no approximations except the usual neglect of the viscous forces and terms bilinear or higher in the acoustic fields. For quasistatic or "frozen" turbulence, closed integral forms of these equations are derived. The Digitized Green Function method (1) is applied to these and the scattering cross sections of several model turbules are obtained and compared with crosssections predicted by several of the more current approximate wave equations.
 Publication:

Ph.D. Thesis
 Pub Date:
 1993
 Bibcode:
 1993PhDT.......138D
 Keywords:

 Physics: Acoustics; Physics: Atmospheric Science