Piecewise continuous distribution function method: Fluid equations and wave disturbances at stratified gas

Abstract

Wave disturbances of a stratified gas are studied. The description is built on a basis of the Bhatnagar -- Gross -- Krook (BGK) kinetic equation which is reduced down the level of fluid mechanics. The double momenta set is introduced inside a scheme of iterations of the equations operators, dividing the velocity space along and opposite gravity field direction. At both half-spaces the local equilibrium is supposed. As the result, the momenta system is derived. It reproduce Navier-Stokes and Barnett equations at the first and second order in high collision frequencies. The homogeneous background limit gives the known results obtained by direct kinetics applications by Loyalka and Cheng as the recent higher momentum fluid mechanics results of Chen, Rao and Spiegel. The ground state declines from exponential at the Knudsen regime. The WKB solutions for ultrasound in exponentially stratified medium are constructed in explicit form, evaluated and plotted.

20 pages, 7 figures, 14 ISNA conference, 1996

References in corpus (2)

• A Continuum Description of Rarefied Gas Dynamics (II)--- The Propagation of Ultrasound
• Piecewise continuous partition function method in the theory of wave perturbations of inhomogeneous gas

Cited by in corpus (4)

• Prediction of shock structure using the bimodal distribution function
• One-dimensional ultrasound propagation at stratified gas: Gross-Jackson model
• Fluid dynamics at arbitrary Knudsen on a base of Alexeev-Boltzmann equation: sound in a rarefied gas
• Piecewise continuous distribution function method and ultrasound at half space