Applied Underwater Acoustics

2.5. Sound Reflection and Transmission at a Fluid–Fluid Boundary

The integral-transform technique used above in solving the wave equation for the acoustic field in a homogeneous, unbounded fluid medium has application also when one or more boundaries are present. A case in point is a single fluid–fluid boundary, as illustrated in Fig. 2.15 showing an upper and lower (semi-infinite) fluid with density and sound speed ρ₁, c₁ and ρ₂, c₂, respectively. Stability requires that ρ₂ > ρ₁. This simple, two-layer model approximates the seawater–sediment interface in situations where the shear wave in the sediment is weak and the sound speed profile on either side of the boundary is uniform.

To derive the field in both regions from a point source located ...