平板边界层参数水槽测量与仿真分析研究

Experimental and numerical investigations of the boundary layer parameters of an underwater flat plate model

利用LDV测试技术,在小型水槽中对零压力梯度的光滑平板边界层进行了平均速度剖面测量。利用测得的速度数据进行从壁面到对数律层尾区全壁面律的拟合求解获得壁面摩擦速度和其他边界层流动参数。在实验测量之外还开展了平板绕流CFD仿真分析,并将实验结果、仿真计算结果和平板经验公式计算结果进行比较。结果表明,基于LDV的全壁面律拟合求解平板表面边界层流动参数具有较高精度,结合仿真分析,可为利用平板开展水中MEMS壁面剪应力传感器标定提供理想的输入。

On the basis of the turbulent boundary layer mean velocity profile over a zero pres- sure gradient flat plate measured in a water flume using Laser Doppler Velocimetry （LDV）, this paper obtains the friction velocity and other boundary layer parameters by using the fit of velocity data to the full boundary layer profile from the wall to the top of the log region. Complementary to the measurements, numerical investigations of the flow field around the flat plate have also been performed. The wall shear stress extrapolated from the profile curve is compared with em- pirical formula results and CFD results. The data agreement shows that the fit of the LDV meas- ured velocity data to the full boundary layer profile is of high precision for measuring the bounda- ry parameters. Combined with simulation analysis, it can provide the ideal wall shear stress input for the calibration of MEMS wall shear stress sensors.