实验研究湍流附面层分离

本文应用二维激光多普勒测速技术和压强探针测量了二元非对称曲面扩张通道内的湍流附面层分离,得到了时均速度、流动平均方向角、正反向间歇流动因子以及静压分布.实验结果表明:附面层沿高度方向存在着明显的压强差,并可用位移厚度曲率做二阶近似修正.分离附面层的位移厚度曲率极大值对应于间歇瞬时分离点.瞬时流动平均方向角与正反向间歇流动因子成线性变化.

2-D Incompressible Turbulent-Layer Separation

Incompressible turbulent boundary-layer separation in a 2-D curved-wall diffuser was studied by using 2-D laser doppler velocimeter and pitot-tube probe.Mean velocities,Reynolds shear stresses and upstream-downstream intermittency as well as static pressure were measured.The experimental analysis showed that,there is a significant nor- mal pressure difference near the turbulent-boundary-layer detachment.The maximum of the pressure difference in the layer is related to the maximum of the displacement thickness curvature and to the position near Intermittent Transtory Detachment.The displacement-thickness curvature was used to form a second-order correction of the nor- mal pressure difference.Flow mean angles varied linearly with the upstream-downstream intermittency.