RAYLEIGH-TAYLOR STABILITY OF A 2-FLUID SYSTEM UNDER A GENERAL ROTATION FIELD

In this paper we investigate the Rayleigh-Taylor instability of a two- fluid layer system under a general rotation field. Gravity is always p erpendicular to the two horizontal layers and rotation has an arbitrar y angle with respect to the vertical. It is found that, in an unstable situation, an increase in the non-dimensional density-difference incr eases the stable angular area of wave propagation, measured with respe ct to the horizontal component of rotation. However, it is found that the vertical component of rotation reduces not only this stable angula r area but also the range in which the horizontal component stabilizes the system according to a previous study by Davalos-Orozco (Fluid Dyn . Res., 12:243, 1993). This decrease in stable area occurs along with a decrease in the growth rate in the unstable region. Numerical analys is of the eigenvalue equation shows that the stable angular area disap pears after the non-dimensional vertical component of rotation attains the value 0.33. Exact and approximate analytical expressions for the critical values are calculated to help to understand the physics of th e numerical analysis.