栅栏绕流减速效应风洞实验模拟

Wind Tunnel Simulation on the Wind Velocity Decrement around Porous Fences

为研究阻沙栅栏的空气动力学效应,利用PIV技术对栅栏绕流的速度场进行了风洞实验模拟,并对其减速效应加以分析评价。结果表明,疏透度对栅栏绕流的平均速度场分布影响比较明显,疏透度越小栅栏后的平均水平风速衰减得越快;栅栏绕流的垂直速度分量在栅栏顶部最大,并随疏透度的增大而减小,影响了栅栏周围沙粒的跃移传输及沉积特征;栅栏后的累计减速率可以用高斯峰值函数来拟合,随疏透度的增大呈先增大后减小的趋势,疏透度η=0.2时累计减速率最大,代表了栅栏减速的理论最佳疏透度。

In order to study the aerodynamics of sand fences,the mean velocity field around porous fences was simulated in wind tunnel based on the PIV technology,and its velocity decrement effect was analyzed and evaluated.The results show that porosity has distinct effect on the mean velocity field,the lower the porosity the faster the mean wind velocity decreased.The vertical velocity component decreases with increasing porosity and shows the maximum value on the top of the fence,and it have potential influence on sand particles sediment transport process by alternating its saltating height.The total reduction coefficient of the mean wind velocity behind the fence can be fitted with a Gaussian peak function with the peak value at η = 02,which represents the theoretical optimal porosity in terms of wind velocity reduction.