Large eddy simulation of turbulent heat transfer in a channel flow with square cylinder

流路壁面での熱伝達促進機構を明らかにするために，平行平板間流路内に正方形柱を設置した流れを対象にLESを用いた数値計算を行った．角柱から放出されるカルマン渦に同期して壁近傍に孤立渦が発生する．角柱後流の広範囲にわたり，カルマン渦対間の壁面方向流れにより熱伝達が促進される．一方，孤立渦は下流側から冷たい流体を巻き込み，熱伝達促進に寄与する．Numerical computation with Large Eddy Simulation (LES) has been conducted in a channel flow disturbed by a square cylinder in order to clarify the mechanism of heat transfer enhancement at the channel wall. Discrete vortices appear near the channel wall in phase with the Karman vortices shed alternately from the cylinder. Heat transfer is enhanced by the Karman vortices due to the wallward flow between the Karman vortex pair in the extensive downstream region of the cylinder. On the other hand, the discrete vortices entrain cooler fluid from the downstream side and contribute to the enhancement of the wall heat transfer