钉螺动水沉降速度研究

Study on Scttling Velocity of Snails in Flowing Water and Flume Experiment

水流输送钉螺同水流输送泥沙一样，是一种复杂的力学过程。本文分析了钉螺在流水中沉降运动的主要作用力及其平衡条件。在水流紊动强度不太大（Ｒｅ＜４×１０￣４）的情况下，可略去竖向脉动分速的影响，钉螺在流水中以等速直线运动形式下沉，据此导得钉螺动水沉速的理论公式。通过水槽试验，对公式进行了检验，并确定其中的主要参数──动水沉降阻力系数。

As sediment particles in suspension,snails(oncomelania hupensis)are transported in riversand canals,however,their transportaiton mechanism is a complex process of mechanics.This paperanalyzes the main action forces and their equilibrium conditions in the process of snails settling. In thecase of lower turbulence intensity(Reynolds number is less than 4 ×10￣4),vertical component of tur-bulence may be reglected to make snails in waterflow settle in form of straight-line epuivelocity movement.Through flume experiment,examination of the formula is made and main parameters,drag co-efficient of settlirig in flowing water are determined. Basic relationship of settling theory in flowing water recommended in this paper and the formuladerived by it may also give a reference to studying movement of river sedimentation.