单个池室竖缝宽度束窄对鱼道水力特性的影响

The Effect of Slot Width Narrowing on Hydraulic Characteristics of Vertical Slot Fishway in Single Tanks

针对实际工程中因施工工艺等原因造成鱼道竖缝尺寸误差对过鱼效果的影响,通过物理模型试验,进行了单个池室竖缝宽度束窄对鱼道水力特性的影响研究。试验表明,当鱼道某个竖缝束窄后,竖缝上游侧池室水深增加并形成壅水曲线,影响范围可达5~15个池室,下游侧池室水深急剧降低后又很快恢复,仅影响1~2个池室。当束窄程度达到40%(k=0.6)时,上游侧水面线壅高为8 cm(原型),故对于实际工程影响有限,但是束窄竖缝处流速显著增大(k=1.0,v=1.1 m/s;k=0.6,v>1.6 m/s),上游相邻竖缝流速略有减小(<10%),下游相邻竖缝流速则无显著变化。由于竖缝流速v随束窄系数k的减小呈幂指数规律增加,极易形成流速障碍。以过鱼对象的突进流速为判断依据,对于国内常见的四大家鱼或高原裂腹鱼,鱼道竖缝宽度的束窄范围应分别控制在16%和29%以内。

In view of the adverse influence of fishway vertical slot size error on fish passing efficiency caused by construction technology and other reasons in practical engineering,the physical model tests of a vertical slot narrowing are carried out to study the induced changes of hydraulic characteristics of the fishway.The experimental results show that the water depth of the upstream side of the vertical slot increases and backwater curve is formed when a vertical slot is narrowed.The influence range can cover 5~15 ponds.The water depth of the downstream side of the vertical slot decreases sharply and then recovers quickly,covering only 1~2 ponds.When the slot width reduces by 40%(k=0.6),the maximum rise of the upstream water surface line is 8 cm(in prototype),so its impact on the actual project is limited.The flow velocity at the narrowed vertical slot increases significantly(k=1.0,v=1.1 m/s;k=0.6,v>1.6 m/s),but the velocity of upstream adjacent vertical slot decreases slightly(<10%),and the velocity of downstream adjacent vertical slot has no significant change.The velocity v of the narrowed slot increases in power exponent with the decrease in the narrowing coefficient k,it tends to form velocity barriers.Based on the burst velocity of the fish passing through,the narrow range of vertical slot of the fishway should be controlled within 16%and 29%respectively,for the fishway passing objects of the four major Chinese carps and plateau Schizothorax Species.