Affecting of riblets shape of nonsmooth surface on drag reduction

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.