脊状表面湍流边界层高阶统计量特性

Research on the Characteristic of High-order Statisticin Turbulent Boundary Layer over Riblets Surface

通过对不同风速下V型脊状表面及光洁平板表面湍流边界层内偏斜系数和平坦系数的测试,对比分析了脊状表面边界层内偏斜系数和平坦系数的分布规律。试验在一小型专用风洞中开展,流场测试中使用恒温式IFA300智能型流动分析仪,测试模型则采用有机玻璃材质的矩形平板结构,且试验中模型表面脊状结构的方向与流向一致。最终研究结果表明,脊状表面湍流边界层内偏斜系数和平坦系数分布规律与平板表面基本一致,但脊状结构的存在降低了距壁面无量纲高度y′<10区域(包括整个粘性底层和过渡区的一部分)的偏斜系数和平坦系数,而对边界层中过渡区以外区域则影响不明显。由此可以推断,脊状结构主要影响边界层流场的近壁区。

Having carried out lots of experimental research of the skewness factor and flatness factor of a smooth plate surface and different V-riblets surfaces in size over different wind velocities,the distributing rules of the skewness factor and flatness factor of riblets surfaces in the turbulent boundary layer is acquired.The experiment is carried out in a special small-sized wind tunnel.The flow field is tested using a TSI-IFA300 hot wire anemometer.The test models,which are made of organic glass,are lain to make sure the riblets are streamwise.Ultimate results show that the distributing rules of the skewness factor and flatness factor of the riblets surfaces are similar with the smooth plate.The skewness factor and flatness factor fall in the whole viscous sublayer and a part of buffer zone near wall caused by riblets when is lower than 10,but riblets can＇t produce an obvious effect out of the buffer zone in boundary layer over riblets surface.So we can make conclusions that the existence of the riblets mainly changes the near-wall flow field.