壁面粗糙度湍流扩展模型及流动数值模拟  

Roughness for wall turbulence extension model and flow numerical simulation

作　　者：刘通 蔡晋生[1] 屈崑[1] LIU Tong;CAI Jinsheng;QU Kun(School of Aeronautics,Northwestern Polyteehnieal University,Xi＇an 710072,China)

机构地区：[1]西北工业大学航空学院,西安710072

出　　处：《航空动力学报》2018年第8期1981-1989,共9页Journal of Aerospace Power

摘　　要：采用有限体积法数值求解雷诺平均Navier-Stokes流动控制方程,数值模拟表面粗糙度对气动特性和热力学特性的影响。通过修正Knopp的基于切应力输运k-ω湍流模型的粗糙度湍流扩展模型中边界条件ω的值,提高了壁面附近的涡黏度,增加了总壁面切应力,从而引入壁面粗糙度的影响。通过对不同粗糙度的平板流动和NACA 65_2215翼型绕流进行数值模拟,分析粗糙度对表面摩阻系数、斯坦顿数和升力系数的影响。计算结果表明:粗糙度使得平板表面摩阻系数和斯坦顿数增大,翼型流动分离提前,升力系数减小。流经粗糙壁面的流动处于过渡状态时,改进的粗糙度湍流扩展模型改善了原模型速度偏移量与经验公式相比偏小的缺点,同时,表面摩阻系数、斯坦顿数和升力系数与实验结果吻合得更好。该改进模型不需要对壁面附近网格进行加密,能够快速、准确地模拟流经粗糙壁面的流动。Reynolds average Navier-Stokes equations were solved based on finite volume method to simulate the surface roughness＇s influence on aerodynamic and thermodynamic characteristics.To account for the effect of wall roughness,the wall-value ofωof Knopp＇s roughness extension for shear stress transport k-ωtwo equations turbulence model was modified to increase near wall eddy viscosity and total wall shear stress.Flows over flat plate and past NACA 65_2215 airfoil were simulated and the influences of roughness on skin friction coefficient,Stanton number and lift coefficient were analyzed.The predicted results showed the roughness increased the skin friction coefficient and Stanton number,shifted separation upstream and decreased the lift coefficient.The shift of velocity profile matched well with theoretical results when flow was in transitional regime compared with the roughness extension by Knopp,meanwhile,skin friction coefficient,Stanton number and life coefficent agreed better with experiments.The extension model allows for the simulation of flows over rough surfaces quickly and preciously at the same grid resolution requirements as for smooth walls.

关 键 词：壁面粗糙度 边界层 表面摩阻 湍流扩展模型 平板 翼型 

分 类 号：V211.3[航空宇航科学与技术—航空宇航推进理论与工程]