Acoustic radiation from a finite length cylindrical shell excited by an internal acoustic source: Solution based on a boundary element method and a matched asymptotic expansion (Q1961110)

The authors present a simplified method for the calculation of time-harmonic fields radiated by torpedoes. It is assumed that a cylindrical shell of finite length is filled with a gas and immersed in a fluid. The motion is caused by a point isotropic source located at the center of the system. The air volume is bounded by two bulkheads; one of them provides a clamping boundary condition, and the other a free boundary condition. The equations of motion include Helmholtz equation and a shell operator matrix; additionally, the authors impose Sommerfeld radiation condition. The authors derive a boundary integral for radiated pressure, a boundary integral for shell displacement, and Green representation for inner pressure. The solution obtained is valid for all frequencies, except for the eigenfrequencies. To avoid this difficulty, the authors use the so-called light fluid approximation which allows to represent the solution near singular points. A computer program is developed to calculate the corresponding field components. The results obtained are compared with a similar situation (a baffled cylincrical shell).