Mixed convection in cavities with a locally heated lower wall and moving sidewalls

A numerical study is conducted to investigate the transport mechanism of la minar mixed convection in a shear- and Buoyancy-driven cavity having a loca lly heated lower wad and mooing cooled sidewalls. Effort is focused on the interaction of forced convection with natural convection. Localized heating is simulated by a centrally located heat source on the bottom wall, and fo ur different values of the dimensionless heat source length, epsilon, 1 / 5 , 2 / 5, 3 / 5 and 4 / 5 of the nondimensional length of the bottom wall, a re considered. parametric studies on the effect of mixed convection paramet er, Gr / Re-2 (also referred to as Richardson number, Ri), in the range 0.1 -10, on the fluid flow and heat transfer are performed for each epsilon. Lo cal results are presented in the form of streamline and isotherm plots as w ell as the variation of local Nusselt number on the heated wall. Three diff erent regimes are observed with increasing Gr / Re-2:forced convection (wit h negligible natural convection), mixed convection (comparable forced and n atural convection), and natural convection (with negligible forced convecti on).