Line integral model of transient radiation from planar pistons in baffles

This paper studies transient sound radiation from planar pistons with unifo rm source signal distribution in rigid and pressure release baffles and use s a model with a plane wave term plus an edge wave term. In [H. D. Mair, L. Bresse, D. A. Hutchins, J. Acoust. Soc. Am. 84 (1988) 1517-1525], analytic expressions were derived for the edge wave term. Here, a modified version is presented which restates the edge wave term as being generated by edge s ources for which analytic directivity functions are derived. These directiv ity functions offer further qualitative insight into the concept of a pisto n edge wave and makes efficient numerical implementations possible. Numeric al implementations are discussed and it is shown that discrete-time represe ntations of the impulse responses can be found via an efficient integration along the edge segments. The sound radiation from a circular piston is stu died and the on- and off-axis sound field is calculated using both analytic al expressions and the edge source model with the circle approximated by a polygonal shape. Excellent agreement results, even for the transients which correspond to singularities in the analytic expressions.