仿生非光滑用于旋成体减阻的试验研究

基于仿生非光滑表面具有减粘降阻特性的基本思想,通过仿生非光滑表面控制旋成体附壁区的边界层结构来减小旋成体的阻力。利用6因素3水平的正交试验,考察了对旋成体阻力影响较大的6个因素。对具有不同尺寸的凸包、凹坑以及棱纹等形态的非光滑旋成体及光滑旋成体进行了低、亚、超音速风洞试验,并将减阻率作为试验指标。对减阻率的分析表明,三种非光滑表面均能起到减小旋成体阻力的作用,总阻力最大减阻效果为5%左右。用极差法进行正交试验设计分析,得到了影响旋成体阻力因素的主次顺序及最优水平,并探讨了不同仿生表面对旋成体粘性前部阻力(包括表面摩擦阻力及激波阻力等)及底部阻力的不同影响。

Experimental Study on Drag Reduction for Bodies of Revolution Using Bionic Non-Smoothness

In view of the idea that the bionic non-smooth surface can reduce the viscous drag of a body, the drag reduction potential was investigated for the bodies of revolution by controlling the surface boundary layer structure to form a certain non-smoothness. An orthogonal test scheme with 6 factors and 3 levels for each factor was used to evaluate the effect of 6 major influencing factors on the drag of the bodies of revolution. The non-smooth bodies of revolution with spherical convex domes, spherical dimples and riblets were tested in comparison with the original smooth body in a wind tunnel under low speed, subsonic and supersonic conditions to get the drag reduction rates of the non-smooth bodies as the test targets. The test results in-dicated that all 3 kinds of non-smooth surfaces can reduce the drag of bodies of revolution, the maximal reduction rate is about 5%. The extremum difference analysis was used to determine the influence order of the factors and their optimal levels. The impact of the different bionic surfaces on the viscous forebody drag (in-cluding the skin friction and the shock-wave drag) and the base drag of bodies of revolution were discussed.