Combined forced and free convection flow on vertical surfaces

Combined free and forced convection flow about inclined surfaces in porous media

The articles in this chapter are introduced as a group rather than individually. The pieces by Mr. Nowzad and Dr. Baker are general surveys of recent developments in Africa and Latin America respectively. Both analyze the recent proliferation of regional and sub-regional organizations in these two continental areas. This ferment is indicative of the ongoing efforts to mold viable political institutions out of a confusing welter of nationalistic goals and aspirations in these regions.

A Survey of Recent Developments

A buoyancy-driven system can be unstable due to two different mechanisms—one mechanical and the other involving buoyancy forces. The mechanical instability is of the type normally studied in connexion with the Orr-Sommerfeld equation. The buoyancy-driven instability is rather different and is related to the ‘Coriolis’-driven instability of rotating fluids. In this paper, the stability of a buoyancy-driven system, recently called a ‘buoyancy layer’, is examined for the whole range of Prandtl numbers, s. The buoyancy-driven instability becomes increasingly important as the Prandtl number is increased and so particular interest is attached to the limit in which the Prandtl number tends to infinity. In this limit, the system is neutrally stable to first order, but second-order effects render the flow unstable at a Reynolds number of order σ-½. Consequences of the results for the stability of convection in a vertical slot are examined.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022112069001431

Albin A. Szewczyk

Papers

Combined Forced and Free-Convection Laminar Flow

Stability and transition of the free-convection layer along a vertical flat plate

An Approximate Treatment of Unsteady Heat Conduction in Semi-Infinite Solids With Variable Thermal Properties