Acoustic time-dependent energy and instantaneous power from planar radiators via a generalized radiation impulse response approach.

Abstract

The radiation impulse response, which is the temporal Fourier transform of the radiation impedance, provides the basis for a convolution approach to evaluate the time-dependent force, instantaneous power, and energy transfer into the fluid resulting from a separable space-time normal velocity of a fluid loaded surface. After a brief review of the radiation impulse response approach to address such problems for planar radiators, several specific examples for planar radiators are addressed. General results for the temporal evolution of the energy from a baffled planar source of arbitrary shape with a specified space-time separable normal velocity distribution are developed. The case of a circular piston in an infinite rigid plane is then addressed to illustrate the time-dependent force, instantaneous power, and energy transfer into the fluid for pulsed velocity excitations. In particular, the energy exchange between the incompressible near field and the acoustic far field is addressed for the pulsed excitations.