CAJ | 학술논문

快速游动的鲨鱼，其皮肤表面布满沿流动方向的沟槽，这种沟槽能够减小鲨鱼游动过程中的阻力。通过仿生技术人们设计了一系列具有单一尺度的沟槽结构，如V型、L型、U型等（定义为原始沟槽），并获得了一定的减阻效果。然而通过仔细观察，发现鲨鱼皮肤表面的沟槽并非是单一尺度的。根据这一启发，通过在原始V型沟槽顶部两侧增加小尺度三角形突起，设计了一种二级沟槽表面。利用RNG k-ε湍流模型，对原始V型沟槽和二级沟槽表面进行了流场分析。讨论了在不同雷诺数的情况下，两种沟槽壁面对湍流边界层内速度分布、沟槽壁面切应力及减阻效果的影响。计算结果表明，在一定雷诺数范围，原始V型沟槽最佳减阻4．6％，二级沟槽结构最佳减阻8．07％，二级沟槽减阻效果明显优于原始V型沟槽。二级沟槽表面能够更有效地抑制边界层内湍流流动，减小了流体流动的黏性阻力，具有更好的减阻效果。
쾌속유동적사어，기피부표면포만연류동방향적구조，저충구조능구감소사어유동과정중적조력。통과방생기술인문설계료일계렬구유단일척도적구조결구，여V형、L형、U형등（정의위원시구조），병획득료일정적감조효과。연이통과자세관찰，발현사어피부표면적구조병비시단일척도적。근거저일계발，통과재원시V형구조정부량측증가소척도삼각형돌기，설계료일충이급구조표면。이용RNG k-ε단류모형，대원시V형구조화이급구조표면진행료류장분석。토론료재불동뢰낙수적정황하，량충구조벽면대단류변계층내속도분포、구조벽면절응력급감조효과적영향。계산결과표명，재일정뢰낙수범위，원시V형구조최가감조4．6％，이급구조결구최가감조8．07％，이급구조감조효과명현우우원시V형구조。이급구조표면능구경유효지억제변계층내단류류동，감소료류체류동적점성조력，구유경호적감조효과。
The skin surface of fast swimming shark’s is covered with grooves along the flow direction,which is proved to be able to reduce resistance in swimming.Using bionic technology,a series of trench structures with single scale is designed,such as V-shaped,L-shaped,U-shaped,etc.(defined as the original trench),and some drag reductions are acquired.Considering that the grooves covered on shark skin surface do not have a single scale,a secondary micro-grooved surface is designed in this paper by adding small-scale triangle on the top of the V-shaped grooves on both sides.Using RNG k-εturbulence model,the flow field of original V-shaped grooves and secondary micro-grooved surface were analyzed.With different Reynolds numbers,the effects of two trench walls on the velocity distribution in the turbulent boundary layer,shear stress of the trench wall and drag reduction were discussed.The results show that,in a certain range of Reynolds number,secondary micro-groove reduce the resistance by 8.07%,while the original V-shaped groove shorten the resistance by 4.6%.The secondary micro-grooved surface is more effec-tive in inhibit the turbulent flow in boundary layer and reduce the viscous resistance in fluid flow,and has a better drag reduction characteristics.