Sound scattering by a hard axisymmetric object in a double layered ocean

An acoustically hard object is placed in a double layered ocean very far from a point source of acoustic waves. The object is either floating in the water layer or buried in the sediment layer. Both layers are homogenous. The size of the object is small when compared to the depth of the water channel. The free surface of the sea is assumed to be soft and the bottom is assumed to be hard. Between the two layers the classical diffraction boundary conditions are taken. The deep water approximation method is being extended to provide an approximating analytical expression of the scattered pressure field.