Bragg scattering of sound by surface waves in shallow water

Abstract

We present a theory of Bragg scattering of sound by surface gravity waves which are nearly periodic with a slowly varying envelope. Through several examples we illustrate how the resonant scattering of sound from a CW source in shallow water can reveal the characteristics of weak surface waves. Only plane sound waves of a guided mode are studied in this paper. Specific examples include the scattering by surface waves which are modulated in amplitude and/or phase. The incident sound waves are sinusoidal but detuned. Applications to short surface waves riding on long surface waves are examined.