Coupled Convective and Morphological Instability in a Simple Model of the
Solidification of a Binary Alloy, Including a Shear Flow
Shaun A Forth & Adam A Wheeler
Published in
Journal of Fluid Mechanics 236 pp61-94, (1992)
Abstract
In this paper we provide a detailed description of
the interaction of solutal convection and morphological instability in the
presence of a model boundary-layer flow. We present a detailed investigation of
the marginal surfaces in Rayleigh-number, Sekerka-number, Reynolds-number space
associated with a linear stability analysis. We give mathematical arguments and
physical mechanisms to explain the results and present a coherent description of
this complicated situation, We identify two new modes, one convective and one
morphological. We show that the oscillatory so-called `mixed' modes that result
from the coupling of morphological and convective modes play a central role in
the unfolding of the solution structure by the shear flow. This flow has the
effect of decoupling the convective and morphological modes. 