KINETIC ALPHA-EFFECT IN VISCOSITY STRATIFIED CREEPING FLOWS

It is shown that viscosity stratified plane Poiseuille flow may exhibi t a long-wavelength instability of a purely kinetic nature formally re sembling the so-called alpha effect known in magnetohydrodynamics or i n anisotropic three-dimensional flows of homogeneous fluids. In the ab sence of the alpha effect, the system may display a peculiar type of l ong-wavelength instability, where the latter is controlled by the surf ace tension. The weakly nonlinear equation for the evolving interfaces is derived and solved numerically. (C) 1995 American Institute of Phy sics.