Excitation of the entropy mode in the field of intense sound, that is, acoustic heating, is theoretically considered 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 with an acoustic driving force which is quadratically nonlinear in the leading order. The diffusion coefficient is proportional 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 impulsive sounds. Acoustic heating in a half-space and in a planar resonator is discussed. The aim of this study is to evaluate acoustic heating and determine the contribution of thermal conduction and mechanical viscosity in different boundary problems. The conclusions are drawn for the Dirichlet and Neumann boundary conditions. The instantaneous dynamic equation for variations in temperature, which specifies the entropy mode, is solved analytically for some types of acoustic exciters. The results show variation in temperature as a function of time and distance from the boundary for different boundary conditions.

JO - Archives of Acoustics L1 - http://journals.pan.pl/Content/112095/PDF/aoa.2019.128495.pdf L2 - http://journals.pan.pl/Content/112095 IS - No 2 EP - 328 KW - nonlinear acoustics KW - acoustic heating in resonators KW - Burgers equation KW - first and second type boundary conditions KW - acoustic heating in a half-space ER - A1 - Perelomova, Anna PB - Committee on Acoustics PAS, PAS Institute of Fundamental Technological Research, Polish Acoustical Society VL - vol. 44 JF - Archives of Acoustics SP - 321 T1 - Impact of Boundary Conditions on Acoustic Excitation of Entropy Perturbations in a Bounded Volume of Newtonian Gas UR - http://journals.pan.pl/dlibra/docmetadata?id=112095 DOI - 10.24425/aoa.2019.128495