Turbulent thermal convection in a cell with ordered rough boundaries

A novel convection experiment is conducted in a cell with rough upper and l ower surfaces. The measured heat transport in the rough cell is found to be increased by more than 76%. Flow visualization and near-wall temperature m easurements reveal new dynamics for the emission of thermal plumes. The exp eriment shows that the interaction between the horizontal shear flow due to the large-scale circulation and the ordered rough surface creates a second ary flow (eddies) in the groove region. The secondary how together with the large-scale circulation enhance the detachment of the thermal boundary lay er from the tip of the rough elements. These extra thermal plumes are respo nsible for the enhanced heat transport in the rough cell. The discovery of the enhanced heat transport has important applications in engineering for m ore efficient heat transfer.