PIV技术及其在风沙边界层研究中的应用

 为了考察粒子图像测速度技术在风沙环境风洞中的测量精度及在风沙边界层研究中的应用潜力，通过筛选适当的示踪颗粒，借助PIV测量系统重新测量了风沙环境风洞中的风廓线，并获得了风沙边界层内跃移沙粒的速度和浓度分布规律。实验结果表明：PIV测得的风速廓线与标准风速廓线仪所测结果相当吻合(R2≥0.99);沙粒跃移的平均水平速度和相对浓度（灰度）沿距离沙面高度分别呈幂函数和负指数分布，沙粒速度随高度和自由风速的增加而增大，相对浓度随高度的增加而快速衰减，风速越小衰减越快，风速越大衰减越慢，这一结果与前人的结论一致。PIV系统为将来能够进行更加精确的风沙运动微观机理研究提供了技术保证。

PIV Technology and Its Application in Blowing Sand Boundary Layer Research

In order to test the accuracy of particle image velocimetry in wind tunnel and its application potential in blowing sand boundary layer research,seeding particles were selected as tracer and the wind velocity profile was re-measured,the distribution law of sand particle velocity and concentration was also obtained.The results suggested that the wind velocity profile measured by PIV fits well with the standard wind profiler's result.The mean horizontal particle velocity changes with the height above the sand tray in power function,and the relative particle concentration changes with the height above the sand tray in exponential function.The mean horizontal particle velocity increases with the increase of the height and wind velocity,but the relative particle concentration decays with the height.The smaller the wind velocity the faster the relative particle concentration decays and vice versa.The results in this experiment agree well with those proposed in most previous studies,which reveal that PIV system assures the technical support on more accurate microcosmic research on aeolian sand movement in future.