Acoustic wave generation by thermal excitation of small regions

Abstract

Reciprocity theory is used to derive a general formalism for generation of acoustic waves by thermal excitation. It is shown that the most important parameters contributing to the generation include the thermal expansion of the material and its interaction with the volume dilation associated with the acoustic field of the receiving transducer. The excitation of a longitudinal acoustic wave, as a function of angle to the surface normal, is derived directly.