Issue
EPL
Volume 88, Number 3, November 2009
Article Number 30012
Number of page(s) 6
Section General
DOI http://dx.doi.org/10.1209/0295-5075/88/30012
Published online 19 November 2009
EPL, 88 (2009) 30012
DOI: 10.1209/0295-5075/88/30012

A new effect of the nongradient transport in relaxation zones

V. V. Aristov, A. A. Frolova and S. A. Zabelok

Dorodnicyn Computing Centre of the Russian Academy of Sciences - Moscow, Russia

aristov@ccas.ru
afrol@ccas.ru
serge@ccas.ru

received 16 July 2009; accepted in final form 22 October 2009; published November 2009
published online 19 November 2009

Abstract
The nontraditional transfer properties in the spatially nonuniform relaxation regions are studied by the methods of kinetic theory applied to gas mixtures and gases with inner degrees of freedom. Direct numerical methods for solving the Boltzmann and kinetic model equations are used. The influence of the nonequilibrium boundary distribution functions and consequently of boundary fluxes of dissipative values on the gradients of some moments is studied. It is found that in the relaxation zones which are formed by the supersonic nonequilibrium boundary conditions the gradients of velocity and temperature can have the same signs as the appropriate component of the nonequilibrium stress tensor and heat flux, respectively, which is an example of the nongradient transport differing from the classic Stokes and Fourier transport. The physical sense of this formulation of the problem is discussed. 1D and 2D nonuniform relaxation problems are considered and examples of the anomalous transport are presented.

PACS
05.20.Dd - Kinetic theory.
47.45.Ab - Kinetic theory of gases.
51.10.+y - Kinetic and transport theory of gases.

© EPLA 2009