二维非光滑凹坑面减阻性能数值仿真分析

Numerical Simulation and Analysis of Drag Reduction on Dimple Concave 2D Non-Smooth Surface

湍流减阻技术是美国NASA研究中心列出的21世纪航空关键技术之一。目前国内外仿生非光滑面减阻技术研究主要集中在沟槽减阻,对非光滑凹坑面减阻研究较少。为进一步分析凹坑面在空气介质中流动具有的减阻效果与减阻性能,用Fluent软件初步对二维凹坑面在空气介质中的流动进行了数值仿真。发现由一系列半圆与间隔组成的凹坑面在来流速度为6m/s^15 m/s时具有良好的减阻效果,当速度为6m/s时,总减阻量最大可达到18.84%。粘性摩擦阻力减阻量达到19.98%。最后分析了该尺寸二维凹坑面减阻机理,认为凹坑结构能产生影响边界层的流动漩涡,减小了凹坑面附近的速度梯度,从而使表面摩擦阻力减小。

Turbulent drag reduction technology is listed as one of the key technologies of the 21 st century by NASA. In order to further analyze the concave surface in the air medium flow with the drag reduction effect and drag reduction performance, 2D non-smooth surface with dimple concave in air flow was numerically computed and simulated using FLUENT software. Compared with the smooth surface flow field comparison, this kind of unsmooth surface （with dimple concave） had a good drag reduction effect. And it had the best drag reducing ability （drag reduction amount to 18.84%） at a velocity of 6 m/s. Viscous friction drag reduced amount to 19.98%. The theory of the drag reduction was finally analyzed. The results prove that the concave structure can influence the boundary layer flow vortex, reduces the pit wall near the velocity gradient, so that the surface friction resistance reduction.