透空潜坝附近水流特性的数值模拟

透空式潜坝是一种兼顾生态和环境的新型整治建筑物。为深入了解透空潜坝附近水流特性，基于N-S方程和不可压缩气液两相流理论建立三维数值水槽，对梯形透空式潜坝附近水流特性进行数值模拟，研究了透空率、水深和流速对潜坝附近流场、紊动能和涡量等水流特性的影响规律。结果表明:相同水流条件下，随着透空率的增大，坝后回流流速减小，坝后根部紊动强度逐渐增大，而坝后1~4倍坝高范围内紊动强度逐渐减小，涡量先增大后减小。透空率不变情况下，在相同断面平均流速条件下随着水深增大，透水率逐渐减小，潜坝附近紊动强度整体减小，但紊动范围变化不大，坝顶强涡量区面积减小。在相同水深条件下随着断面平均流速增大，涡旋回流强度逐渐增大，潜坝附近高紊动区紊动强度整体也增大, 坝体顶侧和透水圆孔附近正负涡量间隔分布，强度逐渐增大。

Numerical simulation of flow characteristics near the permeable submerged dam

The permeable submerged dam is a new rectification building that takes into account both the ecology and the environment. In order to understand thoroughly the flow characteristics near the permeable submersible dam, based on the N-S equations and the theory of incompressible gas-liquid two-phase flow, a three-dimensional numerical model was developed to numerically simulate the flow characteristics near a trapezoidal permeable submerged dam. The influence of penetration rate, water depth and velocity on the flow characteristics, turbulent kinetic energy and vorticity flow around submerged dams was studied. The results show that under the same flow conditions, with the increase of the permeability, the reverse flow velocity decreases and the turbulent intensity of the root of the dam increases gradually, while the turbulence intensity decreases gradually in the range of 1~4 times the height of the dam, and the vorticity increases firstly and then decreases. Under the same permeability, with the condition of the average flow velocity at the same cross section, the seepage flow rate gradually decreases as the water depth increases, the turbulence intensity near the submerged dam decreases as a whole, but the variation of the turbulent range is not large, and the area of the strong vorticity area of the dam is also reduced. Under the same water depth condition, with the increase of the average flow velocity of the section, the vortex reflow intensity increases gradually, and the turbulence intensity around the submerged dam also increases, positive and negative vortices are staggered and distributed between the top side of the dam body and the pervious round hole, and the vortices strength gradually increases.