ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06
3aPA1. Acoustic radiation pressure in an infinite lossy medium.
Zhong-Yue Jiang
James F. Greenleaf
Dept. of Physiol. and Biophys., Mayo Clinic and Foundation, Rochester, MN
55905
Theories on acoustic radiation pressure associated with plane acoustic
waves and lossless media have been examined extensively. The radiation pressure
produced by a non-plane wave in a lossy unbounded medium was analyzed. The
distinction between Lagrangian and Eulerian pressure was used to clarify the
understanding of radiation pressure. The radiation pressure exerted on a
perfectly absorbing pointwise target by an arbitrary acoustic wave in an
unbounded lossy medium was then considered. By using an indirect approach
developed in Chu and Apfel [B.-T. Chu and R. E. Apfel, 1673--1687
(1982)], the radiation pressure was analyzed without appealing to the detailed
solutions of the governing fluid dynamic equations. It was shown that even in
lossy media with arbitrary waves, the radiation pressure experienced by a
pointwise target is equal to the Langevin pressure which is the time average
energy density at that point. The radiation pressure exerted on a specific
target by an arbitrary acoustic wave in an infinite lossy medium was studied
and a concise theoretical result was obtained. [The work was supported by
grants CA 43920 and HL 41046 from the National Institutes of Health.]