Acoustic field radiated by an impulsively excited line source of finite length

Abstract

A new closed-form theoretical expression is derived that describes the transient acoustic pressure field that is radiated when a line source of finite length impulsively excites the fluid surrounding it. The new expression, which is obtained by solving the two-dimensional scalar wave equation by integral-transform techniques,describes the acoustic field of the finite line, in the time-domain, in terms of generalized functions. The results obtained, which support the ideas advanced in the Rubinowicz-Maggi diffraction theory, show that the field of a line source is comprised of three distinct components: a spatially discontinuous cylindrical wave (“geometrical wave”) and two directional boundary-diffraction waves radiated by the ends of the line. There is a direct analogy between the results reported in this paper and those given by Schoch in his classic paper on the radiated acoustic fields of planar sources.