ACOUSTIC RADIATION PRESSURE IN A 3-DIMENSIONAL LOSSY MEDIUM

Acoustic radiation pressure exerted by an arbitrary acoustic wave in a three-dimensional lossy medium is calculated by extending an indirect approach developed by Chu and Apfel [B-T. Chu and R. E. Apfel, ''Acou stic radiation pressure produced by a beam of sound,'' J. Acoust. Sec. Am. 72, 1673-1687 (1982)]. Without appealing to the detailed solution s of equations governing fluid motion, a general analytic expression f or the radiation pressure in lossy media with arbitrary waves is obtai ned. When an infinite lossy medium is considered, the expression state s that the radiation pressure, to the lowest order of approximation (i .e., second order), is equal to corresponding total energy density. Fo r a special class of confined spaces, the expression leads to a rather general formula for the radiation pressure, in which the radiation pr essure is given in terms of various energy densities in the field. Fur thermore, a relationship among these energy densities is generalized t o the case of lossy media, which enables one to compute the radiation pressure in the class of spaces with the knowledge of the first-order perturbation solution only. (C) 1996 Acoustical Society of America.