振荡流作用下波状底床上流场特性的实验研究

本文利用U型振荡水槽和粒子图像测速仪(PIV)对三种固定波状底床上的流场进行了测量，得到一系列不同振幅条件下的瞬时速度场和涡量场.通过分析不同时段涡强度以及涡轨迹，讨论了底床形状对其附近流场的影响.实验结果分析表明，底床形状决定着整个涡量场特征及涡轨迹，从而决定着泥沙的净输移.这些结果对于探讨浅海区沙波、沙纹和沙垄等波状底床上泥沙输移的力学机制是很有意义的.

Investigation of characteristics of fluid field over wavy beds under oscillatory flow

Particle Image Velocimetry(PIV) has been used to measure the oscillatory flow above three fixed wavy beds in the U-type tank.And the instantaneous velocities and vortices at several amplitudes have been acquired.By analyzing the circulation and trajectory of vortices with varied phases,the influences of beds geometric characteristic on the flow closed to the beds have been carried out.All of these indicate that the wavy beds geometric profiles determine the characteristic of vortex field and the vortex trajectory and the net sediment transport.The conclusions are significant to study the mechanism of sediment transport over wavy beds such as sand waves,ripples and dune for the coastal environment.