Natural Convection Flows and Stability

Abstract

Publisher Summary This chapter discusses laminar and transition flows, external and free boundary flows, and boundary layer regimes. It presents general equations of the natural convection flow and introduces approximations in terms of their physical significance to yield the conventional equations of analysis. The boundary layer simplifications for two-dimensional vertical flows are also discussed followed by the equations for vertical axisymmetric flows. For steady laminar boundary layers arising from the temperature induced buoyancy, known solutions for the vertical and axisymmetric flows are reviewed, including plumes. The combined mass transport and thermally induced buoyancy is treated, consideration is given to laminar transients. The chapter also reviews how laminar flows become unstable and how disturbances amplify to lead the flow toward transition. Vertical flows adjacent to surfaces and in plumes are considered. The nature of transition and turbulent flow are treated. The general question of instability in buoyancy induced flows is also treated. The question of separation in natural convection flow is reviewed and distinctions are drawn relative to the forced flow separation.