INHERENT BACKGROUND COEFFICIENTS FOR SUBMERGED CYLINDRICAL-SHELLS

The scattering of sound waves by an empty, cylindrical, elastic shell in a fluid is considered in the resonance regime. A long-standing diff iculty in the application of the resonance scattering theory is that a n exact expression of the acoustical background has been elusive to fi nd over the years. The exact expression, named the inherent background coefficient, is presented here. The coefficient is uniquely determine d by the generalized fluid-loading-parameter and leads to the impenetr able background coefficient in appropriate limit. Numerical calculatio ns show that it describes the background for a shell of arbitrary thic kness and material correctly over the entire frequency range. (C) 1997 Acoustical Society of America.