基于FLUENT的贯通型鱼巢砌块水力特性研究

Study on Hydraulic Characteristics of Through Fish Nest Block Based on FLUENT

研究鱼巢砌块在不同河流流速下的水力特性,对鱼巢砌块的设计与应用具有重要意义。鉴于目前鱼巢砌块水力特性研究较为薄弱的现状,以一种贯通型鱼巢砌块为例,通过三维数值模拟方法,结合目标保护鱼类的行为习性,探讨不同工况下贯通型鱼巢砌块水力特性,并与物理模型试验结果进行比较。结果表明,鱼巢砌块数值模拟结果与模型试验结果吻合良好,不同工况下鱼巢砌块流态、流速场分布基本相似,即鱼巢砌块内部最大流速虽然随主流流速的增大而增大,但始终小于目标保护鱼类的极限游速,满足鱼类进出砌块的需求;砌块内部流场仅在大流速工况下存在较明显的旋涡区,且最大旋涡尺度始终小于目标鱼类体长,不会对鱼类造成伤害;砌块内部局部最大紊动能随主流流速的增大而增大,但最大值始终小于0.050 m^(2)/s^(2),属于低紊动能区,适合作为鱼类的休憩场所。

The study of the hydraulic characteristics of fish nest blocks at different river flow rates is of great significance for the design and application of fish nest blocks.Aiming at the current situation of the weakness research on hydraulic characteristics of fish nest block,using three-dimensional numerical simulation and considering the behavior habits of target fish protection,this paper studied the hydraulic characteristics of the fish nest blocks under different working conditions and compared with the physical model test.The results show that the numerical simulation result of the fish nest blocks agrees well with the model test.The distribution of fish nest block flow state and flow velocity field is basically similar under different working conditions;Although the maximum flow rate inside the fish nest block increases with the mainstream flow rate,it is always smaller than the limit swimming speed of the target protection fish,which meets the needs of fish entering and leaving the block.The internal flow field of the block has a significant vortex area only under large flow speed conditions,and the maximum vortex scale is always less than the length of the target fish body that will not cause harm to the fish.The local maximum turbulent kinetic energy inside the block increases with the mainstream flow rate,but the maximum is always less than 0.050 m^(2)/s^(2),and it belongs to the low turbulent kinetic energy area,which is suitable as a rest place for fish.