(Neelain University, 2008) Salah Eldin Ahmed Mohammed Eltahir
Abstract
The linear stability analysis of a Newtonian incompressible fluid in
a vertical curved channel formed by two coaxial cylindrical surfaces with
a radial temperature gradient and an azimuthal pressure gradient shows
that the critical modes are oscillatoiy and non-ax symmetric. A
generalized Ray leight dicriminant which includes both the curvature and
buoyancy effect is derived. Centrifugal buoyancy induces week
asymmetry of the dependence of the control parameter critical values on
the sign of the temperature gradient . The critical parameters depend on
the temperature gradient, the radius ratio and the nature of the fluid . For
a wide curvature channel flow ,there are two critical modes : oscillatory
Dean modes for small temperature gradients and oscillatory centrifugal —
thermal modes for relatively large temperature gradients .
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