SINOPSIS

Direct numerical simulation (DNS) of heat transfer in a channel flow obstructed by rectangular prisms has been performed for Re_τ = 30−80, where Re_τ is based on the friction velocity, the channel half width and the kinematic viscosity. The molecular Prandtl number is set to be 0.71. The flow remains unsteady down to Re_τ = 40 owing to the disturbance induced by the obstacle. For Re_τ = 30, the flow resulted in a steady laminar flow. The statistical quantities such as the friction factor and the Nusselt number are discussed by comparison with DNS data of plane channel flows and experimental data.