Numerical Study on MHD Mixed Convection in a Lid Driven Cavity with a Wavy Top Wall and Rectangular Heaters at the Bottom

摘要

A numerical analysis of MHD mixed convection in a lid-driven cavity with a wavy top wall and rectangular heaters at the bottom wall has been carried out in the present study. The lower wall has three rectangular heaters with temperature T_h while the top wall ismaintained partially cold temperature T_c and remaining parts are kept adiabatic. Moreover, both left and right walls are sliding with velocity 5m/s and -5m/s respectively. Two-dimensional Navier-Stokes and energy equationshave been solved by using the Galerkin weighted residual scheme of finite element method. To investigate the effect of Grashof number, Reynolds number, dimensionless height of heaters on the fluid flow and heat transfer characteristics inside the enclosure a set of graphical results has been presented in terms of streamlines, isotherms, temperature, velocity profile and the average Nusselt numbers. A complete study for the effect of Re shows that, the strength of circulation increases with the increase in the value of Re irrespective of Hartmann number and Prandtl number. It is found that those parameters related with geometrical dimension of the heaters affect the temperature distributions, flow fields and heat transfer rate. The method used is validated against with previous works. It was also found that for higher Rayleigh numbers a relatively stronger magnetic field was needed to decrease the heat transfer through mixed convection.