高拱坝坝身泄洪及表孔体型优化数值模拟

Numerical simulations of flood discharge and surface holes shape optimization of high arch dam

泄洪消能技术是高坝水库水力学问题研究的重点。基于Flow-3D软件建立了高拱坝坝身泄洪的三维数值模型,通过有限体积法求解雷诺平均的N-S方程(RANS),湍流模型采用RNG k-ε模型,并通过VOF方法追踪自由液面。通过数值模拟高拱坝表孔、中孔联合泄洪,与物理模型试验数据进行对比,验证了数值结果的准确性。进一步调整表孔出口体型,研究其对坝身泄洪的影响,结果表明:边表孔采用俯角出流方案比平角出流更有利于水垫塘的安全,且随着边表孔俯角的增大,表中孔水舌交汇角增大,空中消能效果提升,下游水位沿程上升减慢。研究成果可为高拱坝泄洪消能设计优化提供参考。

The technology of flood discharge and energy dissipation is the focus of high dam hydraulic research.A 3D numerical model of a high arch dam was developed using Flow-3D software.The Reynolds-Averaged Navier-Stokes equations(RANS)have been solved by the finite-volume method in numerical simulations.The RNG k-εturbulence model was employed and the Volume-of-Fluid(VOF)method was used to capture the movements of the free surface.The numerical results of the joint-flood discharge of high arch dams were verified by comparing with measurements in model tests.Further adjustments on the outlet shape of the surface holes were adopted to study the influence on flood discharge.The results show that side surface holes with a depression angle are more conducive to the safety of the plunge pool than those with a flat angle.With the increase of the depression angle,the confluence angle of water tongues of the surface and middle holes increases,the effect of energy dissipation in air improves,and the rising rate of the water level along the downstream decreases.Present research provides useful guidelines for the design and optimization of flood discharge and energy dissipation of high arch dams.