The generalized Debye series expansion: Treatment of the concentric and nonconcentric cylindrical fluid-fluid interfaces

A new method for the calculation of the scattered field due to a plane wave incident on a structure involving one or several cylindrical fluid-fluid interfaces is presented. This method involves the generalized Debye series expansion (GDSE). The GDSE allowed for the decomposition of the global physical process in a series of local interactions: reflections and refractions at each interface of the scatterer. in this manner, the logical organization of the local interactions is obtained. In this sense the GDSE method brings a better physical understanding than the classical calculation. A detailed analysis for the cases of the fluid cylinder and the concentric fluid shell is presented in order to explain the GDSE construction. The energy conservation law and the characteristic equation are expressed by means of the modal reflection and refraction coefficients. The method is extended for a fluid shell defined by two nonconcentric cylindrical surfaces and for some more complicated cylindrical structures. (C) 1995 Acoustical Society of America.