基于LES的含阻流圆柱竖缝式鱼道水力特性研究

Study on Hydraulic Characteristics of Vertical Slit Fishway with Resistance Flow Based on LES

为解决游动能力弱的小型鱼类在竖缝式鱼道中的上溯需求,在长、短挡板之间的洄游通道中增设阻流圆柱,并利用Hydro 3D开源代码,采用基于LES的数值模拟技术,模拟增设阻流圆柱前后的竖缝式鱼道内流场。结果表明,根据时均流场中流线分布,增设阻流圆柱后,池室内的涡旋区域面积减少,解决了传统竖缝式鱼道内鱼类上溯过程中方向感缺失的问题;池室内湍动能增加20%,提升了水流的能量耗散,降低了鱼类上溯过程中的能量消耗;长、短挡板及阻流圆柱周围涡量增加,可能对鱼类游动过程中身体的稳定性产生不利影响,但根据涡结构可知,阻流圆柱后方涡旋直径小于小型鱼类体长的76%,因此对鱼类游动过程中身体的稳定性影响较小。竖缝式鱼道内设置阻流圆柱可提高游动能力弱的小型鱼类的上溯成功率。

In order to solve the upstream demand of small fish with weak swimming ability in the vertical slot fishway,an anti-flow cylinder is added to the migration channel between the long and short baffles.Hydro 3D open source code and LES-based numerical simulation technology are used to simulate the flow field in the vertical slot fishway before and after the anti-flow cylinder is added.According to the streamline distribution in the time-averaged flow field,the results show that the area of the vortex area in the pool is reduced after adding the blocking cylinder,which solves the problem of lack of sense of direction in the process of fish upstream in the traditional vertical slot fishway.The turbulent kinetic energy in the pool increases by 20%,which raised the energy dissipation of the water flow and reduced the energy consumption during the fish upstream process.The increase of vorticity around the long and short baffles and the blocking cylinder may have an adverse effect on the stability of the fish during swimming.However,according to the vortex structure,the vortex diameter behind the blocking cylinder is less than 76% of the body length of the small fish,so it has little impact on the stability of the fish during swimming.In summary,the setting of a flow blocking cylinder in the vertical slit fishway can improve the success rate of small fish upstream.