仿生非光滑沟槽形状对减阻效果的影响

Affecting of riblets shape of nonsmooth surface on drag reduction

利用有限体积法对三角形、扇贝形和刀刃形三种仿生非光滑沟槽表面流场进行了数值计算。近壁面区采用B-L两层模型,远离壁面区采用雷诺应力模型。分析了三种沟槽非光滑表面的流场特性,对计算域中心Z=3mm平面的速度场和湍流统计量进行了研究,分析了不同沟槽形状对减阻效果的影响,为最佳减阻沟槽设计提供了理论依据。三种沟槽具有相同的特征尺寸,顶点间距s=0.1mm,沟槽尖顶到谷底高度h=0.05mm,与光滑表面相比减阻效果分别为3.2%、9.1%、9.7%,数值计算结果和风洞与油槽实验结果有较好的吻合。

Numerical simulations of fully developed turbulent flow over triangle, scallop and blade riblets biomimetics non-smooth surface were performed to educe the reason of different drag reduction by different riblets, which can provide guide for design optimization riblets. All computations were executed with finite volume analysis in single computational domain, and hexahedron map mesh is applied in triangle and scallop riblet, and tetrahedron free mesh is applied in blade one, B-L two layers model and Reynolds stress model are applied in the near wall and the outer region respectively. Velocity ,shear stress and turbulence statistics including vortices were analyzed. The drag is reduced 3.2 % ,9.1%,9.7 % by triangle, scallop and blade riblets with s = 0.1 mm and h -0.05 mm respectively, which is in good agreement with existing experimental data.