Surface Forward Scattering and Reflection.

This report discusses high frequency 15-60 kHz models of surface forward scattering and reflection that are appropriate for use in acoustic simulations based on ray tracing techniques. Typically, some of the following properties of a pulse after a single surface interaction are needed for modeling purposes 1 the amplitude as a function of time in or near the specular direction for example, this gives pulse elongation 2 the corresponding amplitude statistics 3 the partitioning into scattered incoherent and reflected coherent components in the specular direction and 4 the changes in the frequency spectrum due to the moving surface. At a simplier level, 5 an effective reflection loss may be needed, e.g., for reverberation or one-way propagation simulations. At a more detailed level, 6 two-point statistics at the receiver may be desired. In what follows an attempt will be made to describe models for 1-5, but item 6 will not be addressed. With regard to scattering, it will be assumed that the primary interest for simulations lies in representing the scattered signal by an effective reflection loss due to the difficulty of including forward scattering in simulations. Thus, a detailed description of the angular distribution of the scattered intensity near the specular direction will not be given. Additional keywords computations, equations, bubble absorption, specular reflection, surface roughness, incoherent scattering, statistical analysis, mathematical models.