In present work, the miniature cuboid dimples are arranged in specified interval mode along spanwise direction at the bottom of a rectangular channel, and the depth of the miniature cuboid dimples is much less than the thickness of boundary layer. Large eddy simulation (LES) is employed to probe the flow behavior and heat transfer performance of the channel. The numerical results indicate that protrusion effect, secondary vortex, and local miniature air rolling bearing can be induced by miniature cuboid dimples, which result in the drag reduction and slight variation of heat transfer performance in rectangular channel. The simulation results reveal that the existence of the miniature dimples induces additional slip velocity, which effectively reduces the velocity gradient near the bottom of the channel. The low-speed streaks are widened and the mixing of high-speed and low-speed fluids is inhibited. The secondary vortex generated inside the miniature cuboid dimples increases the thickness of the viscous sub-layer, and the rolling friction between the vortex inside miniature cuboid dimples and the upper fluid above the miniature cuboid dimples replaces the sliding friction between wall and fluid. Compared with the channel without miniature cuboid dimples, more than 6% drag reduction can be obtained with the miniature cuboid dimples.

在目前的工作中，微型长方体凹坑在矩形通道底部沿展向方向以指定间隔方式排列，微型长方体凹坑的深度远小于边界层的厚度。采用大涡模拟 (LES) 来探测通道的流动行为和传热性能。数值结果表明，微型长方体凹坑可引起突起效应、二次涡和局部微型空气滚动轴承，导致矩形通道内的阻力减小和传热性能略有变化。仿真结果表明，微型凹坑的存在会引起额外的滑移速度，有效地降低了通道底部附近的速度梯度。低速条纹变宽，高速和低速流体的混合受到抑制。微型长方体凹坑内部产生的次级涡流增加了粘性子层的厚度，微型长方体凹坑内部的涡流与微型长方体凹坑上方的上层流体之间的滚动摩擦代替了壁与流体之间的滑动摩擦。与没有微型长方体凹坑的通道相比，使用微型长方体凹坑可以获得6%以上的减阻效果。微型长方体凹坑内的涡流与微型长方体凹坑上方的上层流体之间的滚动摩擦代替了壁与流体之间的滑动摩擦。与没有微型长方体凹坑的通道相比，使用微型长方体凹坑可以获得6%以上的减阻效果。微型长方体凹坑内的涡流与微型长方体凹坑上方的上层流体之间的滚动摩擦代替了壁与流体之间的滑动摩擦。与没有微型长方体凹坑的通道相比，使用微型长方体凹坑可以获得6%以上的减阻效果。