Stationary convection and internal gravity waves in compressible liquids : influence of piston effect

Abstract

Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.Fundamental equations of a compressible viscous heat-conducting fluid are derived. The rigorous linear stability analysis has been used for the onset of thermal convection and internal gravity waves. Particular emphasis is placed upon the influence of a thermo-acoustic waves (piston effect) on these phenomena. .This recently found contra-intuitive speeding up of thermal equilibration at constant volume replaced the traditional slowing down in a strongly compressible liquid at constant pressure. Our analysis shows that for the onset of convection the results are coincide with those at fixed pressure proving thereby that the piston effect does not influence the. thermodynamic phenomenon of free convection. However, the dynamic phenomenon of propagation of the internal gravity waves is essentially dependent on the piston effect.