摘要
在低速风洞中来流速度一定的情况下使用IFA300恒温热线风速仪测量了光滑表面和两种不同尺寸的脊状表面湍流边界层平均速度分布剖面,并验证了试验段湍流发展的充分性;通过应用Spalding壁面公式使用最小二乘法精准拟合了实验测量的边界层内层速度分布曲线,得到了湍流边界层壁面摩擦速度并进一步求得湍流壁面摩擦应力,较准确地计算出脊状表面的虚拟原点位置,并通过与对数律公式拟合结果比较分析,证实了该方法更加准确有效.最后分别计算了3种实验模型的湍流边界层动量损失厚度.通过对比脊状表面与光滑表面动量损失厚度和壁面摩擦应力,反映了动量损失厚度的大小与壁面摩擦应力的大小具有一致性,充分证实了脊状表面在湍流中具有一定的减阻效果.
The mean velocity distributions in turbulent boundary layers of smooth surface and two different riblet surfaces are measured with IFA300 constant-temperature anemometer in low-speed wind tunnel to validate the full development of turbulent boundary laye. Friction velocity and wall friction stress of turbulent boundary layer are obtained with the least-squares fitted curve of the sublayer velocity distribution based on Spalding formula, and virtual origin position of riblet surface can be acquired accurately. Moreover, the momentum loss thicknesses of these three experimental models is also calculated. The results show that the drag reduction effect is obvious in turbulent flows due to the riblet surface with the comparsion of the momentum loss thicknesses and wall friction stresses of smooth surface and riblet surface.
出处
《力学学报》
EI
CSCD
北大核心
2009年第1期15-20,共6页
Chinese Journal of Theoretical and Applied Mechanics
基金
国家自然科学基金资助项目(10672136)~~
关键词
脊状表面
湍流边界层
摩擦速度
动量损失厚度
壁面摩擦应力
减阻
riblet surface, turbulent boundary layer, friction velocity, thickness loss of momentum, wall friction stress, drag reduction
