青草沙水库闸下海漫段加糙体消能效应的数值模拟

Numerical simulation of energy dissipation effects of aprons for sluices of Qingcaosha Reservoir

为了进一步提高青草沙水库的换水能力,从雷诺平均Navier-Stokes方程和标准k-ε湍流方程出发,基于流体力学的相关理论和SIMPLE算法,数值模拟加大青草沙水库排水量条件下,下游水闸闸门下游水流特性以及对底部冲刷效应。结果表明:在海漫段布置四脚空心块体进行加糙时,可以调整海漫段近底流速分布,降低海漫段近底流速,而且布置四脚空心块体数量越多,增加糙率的效果越显著。从工程经济角度出发,在距离海漫段入口13 m处布置2排交错排列的四脚空心块体、在35 m和57 m处各布置1排四脚空心块体的方案能达到最佳的消能效果。此外,护面块体间距的减小有利于增大底部的粗糙率和壅高水位,但是对减小护滩段下游的近底流速并不显著。

Based on Reynolds-averaged Navier-Stokes equations （RANS） , a standard k-e turbulent model, fluid mechanics theories, and the SIMPLE scheme, the motion characteristics and scouring effects of the downstream water of a sluice were analyzed numerically with large drainage discharge to further improve the drainage capability of the Qingcaosha Reservoir. The results show that four-legged rocks positioned on the roughened apron can be used to adjust the distribution of near bed velocity, and to decrease near bed velocity of aprons. The more four-legged rocks there are, the better the roughening effects are. From the viewpoint of the project＇ s economy, the scheme, in which two rows of four-legged blocks are settled 13 m from the inlet of the apron, and rows of four-legged blocks are settled 35 m and 57 m, respectively, from the inlet, can have the best energy dissipation effect. Moreover, a decrease of rock spacing can increase the roughness of the bottom and raise the water level, but does not have much effect on the decrease of the near bed velocity downstream of the beach protection.