引航道异重流运动及其淤积

Density Flow and Siltation in Approaching Channel

船闸上、下引航道在闸门关闭期间,只有一头与大河相通,另一头封闭,形成所谓“盲肠河段”。实践证明盲肠河段有浑水异重流潜入,造成严重淤积,给通航造成危害。本文运用动量原理,导得了异重流头部运动速度,并考虑到异重流流量沿程减小,求得了异重流运动速度的微分方程;在低含沙浓度条件下,异重流的速度小,紊动很弱,其中的泥沙运动特点类同于沉淀池。根据沉淀池中泥沙运动轨迹方程及不计紊动扩散作用的泥沙运动连续方程,导得了均匀沙和非均匀沙异重流的流速、深度、含沙浓度沿程变化关系式,以及相应淤积量。

Both approaching channel upstream and downstream lock only has one end connected with the river and the other end closed during the lock closed-up, which is called the 'blind channel '. It is proved from the practice that there exists a muddy density underflow in the 'blind channel 'causing serious siltation and bringing obstruction to the navigation . The author derived the formula for the velocity of the density flow head by applying the momentum theory;and derived the differential equation by taking account of the decrease of the discharge of the density flow along the distance . Under the condition of low sediment content, the velocity of the density flow is small and the turbulance is weak, the movement of sediment behaves like that in the settling basin. According to the equation for the trace of motion of the sediment in the settling basin and the continuous equation for sediment movement without turbulance diffusion, the relationship of the density flew velocity, depth and sediment content along the distance of both uniform and nonuniform sediments and the corresponding silting volumes were obtained.