Publications Repository - Gdańsk University of Technology

Excitation of the entropy mode in the field of intense sound, that is, acoustic heating, is theoreticallyconsidered in this work. The dynamic equation for an excess density which specifies the entropy mode,has been obtained by means of the method of projections. It takes the form of the diffusion equation withan acoustic driving force which is quadratically nonlinear in the leading order. The diffusion coefficient isproportional to the thermal conduction, and the acoustic force is proportional to the total attenuation.Theoretical description of instantaneous heating allows to take into account aperiodic and impulsivesounds. Acoustic heating in a half-space and in a planar resonator is discussed. The aim of this studyis to evaluate acoustic heating and determine the contribution of thermal conduction and mechanicalviscosity in different boundary problems. The conclusions are drawn for the Dirichlet and Neumannboundary conditions. The instantaneous dynamic equation for variations in temperature, which specifiesthe entropy mode, is solved analytically for some types of acoustic exciters. The results show variationin temperature as a function of time and distance from the boundary for different boundary conditions.Keywords:nonlinear acoustics; acoustic heating in resonators; Burgers equation; first and second typeboundary conditions; acoustic heating in a half-space

Authors

• prof. dr hab. Anna Perelomova link open in new tab