ABSTRACT
Free convection may be initiated in fluids by buoyancy forces due to the action of a body force, such as gravity, whenever the material density is not homogeneous. The onset and development of convection in fluids can be adequately studied using the complete Navier-Stokes, energy, and related equations. A simpler technique, commonly used for estimating general criteria for the onset of convection, employs hydrodynamic stability analysis. Free convection or buoyancy-driven convection can be established in an environment in which the fluid density stratification is unstable. Buoyancy-driven convection is established in response to the effects of the buoyancy force resulting from minute differences in the fluid density. The Boussinesq approximation lies at the foundation of buoyancy-driven convection analysis and has been applied extensively with considerable success. The incompressible flow equations are thus sufficient in this case for resolving free-convection flows when used with this approximation, and lead to great reduction in computational effort.
