title: Numerical study of three-dimensional sound reflection from corrugated surface waves.
abstract: When a sound wave propagates in a water medium bounded by a smooth surface wave, reflection from a wave crest can lead to focusing and result in rapid variation of the received waveform as the surface wave moves [Tindle, Deane, and Preisig, J. Acoust. Soc. Am. 125, 66-72 (2009)]. In prior work, propagation paths have been constrained to be in a plane parallel to the direction of corrugated surface waves, i.e., a two-dimensional (2-D) propagation problem. In this paper, the azimuthal dependence of sound propagation as a three-dimensional (3-D) problem is investigated using an efficient, time-domain Helmholtz-Kirchhoff integral formulation. When the source and receiver are in the plane orthogonal to the surface wave direction, the surface wave curvature vanishes in conventional 2-D treatments and the flat surface simply moves up and down, resulting in minimal temporal variation of the reflected signal intensity. On the other hand, the 3-D propagation analysis reveals that a focusing phenomenon occurs in the reflected signal due to the surface wave curvature formed along the orthogonal plane, i.e., out-of-plane scattering.
authors: Research Institute of Marine System Engineering, Seoul National University, Seoul, 151-744, Korea.
authors: Youngmin
authors: Y
authors: Choo
authors: Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0238, USA.
authors: H C
authors: HC
authors: Song
authors: Department of Naval Architecture and Ocean Engineering and Research Institute of Marine System Engineering, Seoul National University, Seoul, 151-744, Korea.
authors: Woojae
authors: W
authors: Seong