A STRAIGHTFORWARD APPROXIMATION TO THE EQUATIONS GOVERNING CONVECTIVEFLOWS IN MULTICOMPONENT FLUIDS

A straightforward non-linear extension of Boussinesq's approximation f or two-component fluids is presented. The perturbative method proposed permits the numerical separation of the different orders in the obtai ned hierarchy of equations. The procedure is useful for the analysis o f buoyancy driven flows and the stability of convective patterns. The fluid layer thicknesses, for which the Sorer and Dufour effects must b e retained in the equations, may be determined. The influence of the h ydrostatic field on the heat equation may be obtained in relation to t he layer thickness. The analysis permits us to obtain useful conclusio ns about the stability in two important examples of this kind of syste m: dry air and salt water. The method may be easily extended to multi- component fluids and to any other physical problem. Copyright (C) 1996 Elsevier Science Ltd.