沟槽面湍流边界层湍流度分布

应用激光测速(LDV)技术对沟槽面湍流边界层湍流度分布进行了精细的测量,实验结果表明,在湍流边界层区域沟槽面湍流度最大值比光滑面要小,但出现的位置比光滑面要远.此外,紧靠沟槽面,即y++<4内,沟槽面有较大的湍流度,说明沟槽面有使近壁区流动紊动增加的趋势.对于y/δ≥0.06的区域,湍流度可用u′\u=2.3 exp (-0.9y/δ)描述,而在y/δ<0.06内,则有u′/u =36.4y/δ.

Turbulent Intensities Distributions over a Riblets Surface

The LDV technique has been used to measure the turbulent intensity distribution of turbulent boundary layer flow over a riblets surface.The experimental results indicate that,in comparision with the smooth surface results,the maximum value of turbulent intensity is smaller,but its occurrence position is farther.Moreover,in the region very near the riblets surface,i.e. y++<4,there exists greater value of turbulent intensities,which means that where the riblets surface enhances the flow turbulence.For y/δ≥0.06,the distribution of turbulent intensity can be described as u′/u=2.3exp(-0.9y/δ),otherwise,u′/u=36.4y/δ.