Exact solution for a density contrast shallow-water wedge using normal coordinates

In the previous work, the exact impulse solution for an isovelocity wedge (ρ≠ρ′, v=v′) was obtained [D. Chu, J. Acoust. Soc. Am. 86, 1883–1896 (1989)]. In the present paper, the same method (normal coordinates) is used but the boundary conditions are modified to satisfy the present problem. Although isovelocity is still a highly idealized situation, it is a better approximation to an actual case than a free/rigid boundary model. The reflections and diffractions are well separated in the time domain. The former can be described accurately by images. When velocity contrast is closed to 1, in the absence of diffracted wave, the total field in a general penetrable wedge may be approximated by the image solution for an isovelocity shallow-water wedge plus the total reflections.