Ecology, Environment and Conservation Paper

INFLUENCE OF INTERNAL WAVES ON UNDERWATER ACOUSTIC PROPAGATION

Seyed Majid Mosaddad, Mojtaba Zangeneh, Gholam Reza Chinipardaz and Gholam Reza Isvand

Abstract

A predictive methodology for received signal variation as a function of ocean perturbations is developed using a ray-based analysis of the effects of internal waves and ocean turbulence on long and short range underwater acoustic propagation. Simulated turbulence is represented using the potential theory line vor-tex approach. Simulations are conducted for long range propagation, 10(X)km, containing internal wave fields with added deterministic effects and are compared to those fields with non-deterministic properties. These results show that long range acoustic propagation has a very strong dependence on the intensity of deterministic fluctuations. Numerical analysis for short range propagation, 10km, was constructed for sound through the following perturbation scenarios: simulated turbulence, an internal wave feild, and a feild of internal waves and simulated turbulence combined. Investigation over a varied initial conditions and perturbation strengths suggests internal wave environments supple the majority of spatial variation and turbulent eddy feilds are primarily responsible for delay fluctuation. Spectra of the variations in mean travel velocity reveal internal wave dominance to be dependent on the intensity of the wave.