Flow pulsation and baffle’s effects on the opposing mixed convection in a vertical channel

This numerical study aims to investigate the effects of a horizontal baffle on the heat transfer characteristics of pulsating opposing mixed convection in a parallel vertical open channel. The influences of the dimensionless pulsating frequency Strouhal number and magnitude A, Prandtl number and baffle position Lb on the velocity and temperature distribution and long-time average Nusselt number 〈Nu¯〉 variation for the system at various Re and Gr/Re2 are explored in detail. Our results show that the channel with both flow pulsation and a baffle gives the best heat transfer. With a larger Re  , the inlet flow pulsation dominates the whole velocity field in the channel. 〈Nu¯〉 always increases with a larger Re, pulsation magnitude A   and Prandtl number. Maximum 〈Nu¯〉 occurs at some specific imposed pulsating frequencies which can be considered to be the natural frequency of the system.