A prediction of drag reduction by entrapped gases in hydrophobic transverse grooves

作     者：WANG Bao WANG JiaDao CHEN DaRong 

作者机构：State Key Laboratory of Tribology Tsinghua University 

出 版 物：《Science China(Technological Sciences)》 (中国科学（技术科学英文版）)

年 卷 期：2013年第56卷第12期

页      面：2973-2978页

核心收录：

学科分类：0810[工学-信息与通信工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0702[理学-物理学] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.51075228 and 51021064) 

主　　题：hydrophobic transverse groove gas skin-friction drag reduction computational fluid dynamics(CFD) 

摘      要：The drag reduction effect of super-hydrophobic surface induced by the entrapped gas is unstable due to the gradual disappearance of the trapped *** this paper,a hydrophobic transverse grooved surface was designed to sustain gas in valleys.A detail numerical simulation was presented to investigate the flow field near the proposed *** water flowed over this surface,the entrapped gas was blocked by the ridges and the solid-liquid interface was replaced by the liquid-gas interface due to the entrapped gas,furthermore the micro-vortex formed in the *** there was an effective slippage between water and solid induced by the entrapped gas,the velocity gradient of boundary layer decreased,which contributed to a remarkable drag reduction ***,considering the extra undesired pressure drag reduction which negatively impacted the drag reduction effect of this method,the total drag coefficient including the viscous drag coefficient and the pressure coefficient was *** effective drag reduction rate of about 15%was achieved and the effect of this method was confirmed by experiments conducted in a high-speed water tunnel when grooves were optimized.