Nonlinear internal wave parameter influences on energy propagation using radiative transport theory.

Abstract

When two trains of nonlinear internal waves roughly align, their lead waves form effective boundaries of an acoustic duct in which energy is trapped. This type of propagation may be considered a scattering process resulting from the broken internal wave fronts between the lead waves. A traditional approach uses adiabatic normal modes and sound speed perturbations to calculate energy propagation along horizontal rays. An alternate is a radiative transport method in which acoustic vertical modes carry energy and a two-dimensional (2D) transport equation describes horizontal propagation. This model has parameters that are related to waveguide properties and are found from physical internal wave features. One parameter incorporates the significant curvature observed in many internal wave fronts. The two solution approaches are compared and contrasted. Data from the Shallow Water ‘06 Experiment are used to specify internal wave parameters and to compare with model calculations. [Work supported by the ONR.]