刚性植物条件下静水中粗颗粒泥沙沉速研究

为了探求水生植物对泥沙沉速的影响,本文在总结泥沙颗粒在水体中沉降的影响因素及阻力系数规律的基础上,在静水中设置不同直径、不同排列密度的不锈钢圆柱细杆模拟水体中不带分叉的刚性植物,分别测定粒径为0.1cm~0.45cm的沙粒沉速,并与没有植物条件下的沉速进行对比。研究结果发现,在试验粒径范围内,含植物水体中泥沙沉速随泥沙粒径、植物密度增大而减小,通过修正阻力系数,推导出考虑植物杆径及植物密度排列的泥沙沉速公式。

Settling velocity of coarse sediment particles in still water with rigid vegetation

In order to investigate the influence of vegetation on settling velocity of sediment particles, the involved factors affecting the settling velocity and drag coefficient were reviewed. Stainless steel bars with circular cross section and different diameters were vertically installed in still water with various spaces to simulate the hydrophytes without crotches inlaboratory. The settling experiments of natural sediment particles with diameters of 0. l ~ 0.45cm in vegetated water were carried out. The results show that the hydrophytes have an obvious effect on the settling velocity of sediment particles by comparing the results with those without hydrophytes. The settling velocity of sediment particles decreases with the density of hydrophytes and grain sizes within the diameter range mentioned above. By means of modifying the drag coefficient, a new formula for computing the settling velocities of sediment particles considering the influence of hydrophytes is proposed.