Direct Numerical Simulation of turbulent channel flow with V-shape turbulators

Direct Numerical Simulations (DNS) are carried out to study the channel flow V-shaped roughness on both wall. The roughness is modeled by the immerse boundary method for passive heat transport in a turbulent channel flow with V-shape square ribs for w/k = 3, 8, 10, 15 (w being the pitch, k the height of the ribs turbulators) with a k/h = 0.25, 0.1 (h being the mid-height of the channel). The angle of inclination of the V-shape turbulators is 45 degrees. Numerical results show that V-shape square ribs are more efficient than square ribs in maximizing the heat transfer. The configuration with w/k = 3, k/h = 0.25 presents the largest heat flux. The increase in the heat transfer is due to a secondary motion which is generated by the V-shape turbulators. Secondary motions at the location of the sidewalls transport the heat out of the cavity of the turbulators to the crest pane.