EFFECT OF DIFFERENTIAL DIFFUSION IN TWO-COMPONENT MEDIA

Examples are presented of an exact solution of a nonstationary problem on the development of convection in a binary mixture (seawater) near an infi nite vertical surface in which the buoyancy disturbances are determined both by the temperature and by the disturbances of the impurity (salt) concentration. Consideration is given to the development of convection in a homogeneous medium near an infinite vertical surface at whose boundary specifi cation is made of constant (after ″switching on″ at the initial moment) heat fluxes and impurities or variations of these substances, i.e., problems with boundary conditions of 1st and 2nd kind are considered. The obtained analytical solutions demonstrate the possibility of a nontrivial effect associated with the difference in the values of the coefficients of transfer of two substances: the infl ows of positive buoyancy may lead, contrary to intuitive notions, to the origination of descending motion of the medium rather than the ascending one. Clarifi cation is provided for the physical meaning of such effects, which can be substantial, for example, in melting of sea ice
   
Author:  L. Kh. Ingel′
Keywords:  convection, two-component medium, differential diffusion, seawater
Page:  437