超疏水表面流场特性及减阻规律的数值仿真研究

摘要

Based on the numerical simulation model of superhydrophobic surfaces flow field, the flow field characteristics and the drag reduction law are studied with superhydrophobic surfaces with the microcos-mic topography in turbulence. The results show that the prominent slip flows on the gas-liquid interface and the conjugated streamwise vortex near the microcosmic topography of superhydrophobic surfaces appear. These factors inhibit the turbulent fluctuation, reduce Reynolds stress and energy loss together, so that the superhydrophobic surfaces generate drag reduction effect; the drag reduction of superhydrophobic surfaces increases with the increase of the free shear area ratios and increases with the increase of the topography periods. There is a qualitative relationship between the drag reduction and the slip, namely the greater slip, the better drag reduction effect.%在建立超疏水表面流场数值仿真模型的基础上，对具有微观形貌的超疏水表面在湍流状态下的流场特性和减阻规律进行了仿真研究。仿真结果显示，超疏水表面气液界面处产生了显著的滑移流动，微观形貌附近出现了成对的流向涡。这些因素共同抑制了湍流脉动，降低了各向雷诺应力，减少了流动能量损失，从而使超疏水表面产生减阻效果；超疏水表面减阻量随自由剪切面积比的增大而增大，随形貌周期的增大而增大，且减阻效果与滑移之间存在定性的关系，滑移越大，减阻效果越好。