Buoyancy drop hysteresis in a two-dimensional countercurrent laminar opposing mixed convection system

Abstract

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.A laminar, twodimensional and opposing mixed convection flow confined inside a vertical channel of finite length with adiabatic walls and discrete and isothermal heat sources has been studied numerically by solving the unsteady twodimensional NavierStokes and energy equations. The dynamical behavior of the system is influence by geometrical parameters and three nondimensional parameters: the Reynolds, Richardson, and Prandtl numbers. Results show that for a fixed value of the Reynolds number, if the Richardson number is increased and then decreased along the same path, hysteresis is noted. To understand the principles of this hysteresis behavior, the dynamical properties of the system are analyzed in detail. Numerical predictions of the velocity and temperature fields show that the descending step size does not change the size of the hysteresis effect.