Instability of a Two-Dimensional Wall Plume

Abstract

Consideration is given to the stability characteristics of two-dimensional wall plumes arising from a line source of heat positioned at the edge of vertical or inclined surface. The disturbance equations are solved numerically on the basis of the linear stability theory for a Prandtl number of 0.7 (air). Two unstable modes exist but no loop appears in the neutral stability curve as a result of merging of their modes. The effect of varying the angle of the surface inclination from downward-facing to upward-facing is to increase instability of the flow. The balance relation of disturbance energy shows that buoyancy forces have destabilizing effects in both modes.