高坝下游水垫塘中三种典型流态的数值模拟

Numerical simulation on three kinds of typical flow patterns in the plunge pool of high dam

用垂向二维k-ε紊流模型数值模拟了高坝下游水垫塘流场结构,并与实测流速值进行了比较.研究结果表明,用该模型及相应的k-ε紊流模型边界条件模拟是可行的.采用该模型分别模拟了下游水深降低、水舌入水角变化时水垫塘内的流场结构,得出了自由冲击射流、淹没冲击射流和面流三种典型流态,描绘了三种流态下水垫塘流体质点的迹线特征,给出了流速、动水压差、紊动能和耗散率的分布规律.研究结果表明,水垫塘应避免出现自由冲击射流流态,可以通过加大水垫深度、减小入水角、控制流态来实现淹没冲击射流或面流流态,以降低底板动水压差、紊动能和耗散率,保证水垫塘的安全运行.

Three kinds of typical flow patterns, the free impact jet, the submerged impact jet and the surface flow in the plunge pool of high dam are simulated by a k-ε turbulence model. The character of path line is described in these three flow patterns, the fluctuated velocity, the hydrodynamic presure,turbulent kinetic energy and turbulent dissipation rate are also given. The results can be as a reference in the design and the application of the plunge pool.