Fluctuating Total Enthalpy as the Basic Generalized Acoustic Field

Abstract: The case for the validity of regarding fluctuating total enthalpy H'(xk,t) as a generalized acoustic field, presented previously for time-stationary fluid motion fluctuations (Doak, 1995), is reinforced by demonstrating that this concept is applicable also to arbitrary fluctuations. For a simple shear flow example, it is shown that the propagation of H'(xk,t) through the layer can be significantly affected by the mean Coriolis acceleration and the mean temperature gradient. Reasons are given to support the author's belief that H'(xk,t) is the basic generalized acoustic field. An outline of a conceptually unified research program is proposed; it is suggested that this program could lead to appreciably improved understanding of the local fluid dynamics involved in the generation and radiation of sound generated aerodynamically, dynamics which is also relevant to the turbulent flow of compressible fluids.