Modelling the influence of wall roughness on heat transfer in thermal convection

Kurzfassung

The work is devoted to investigation of the heat transport in thermal convection, enhanced by the roughness of heated/cooled horizontal plates. The roughness is introduced by a set of rectangular heated/cooled obstacles located at the corresponding plates. Based on the boundary layer equations, a new analytical model for the estimation of Nusselt number deviations caused by the wall roughness is developed and presented. For validation of this model, the transport of heat and momentum in rectangular convection cells is also studied numerically, for different aspect ratios of the obstacles, the height of which is significantly higher than the thickness of the thermal boundary layers.