浅水环境中垂向圆形纯射流的数值模拟

Simulation of vertical round turbulent jets in shallow water

为探求浅水中射流的特性,提出了浅水环境中垂向纯射流的流速分布公式.应用体积率(VOF)方法跟踪处理自由水面,利用重组化群的(RNG)紊动能-紊动耗散率(k-ε)模型,对静止均匀浅水水域中的铅垂圆形单孔纯射流进行了数值模拟,研究了自由面位置和不同区域的流速场分布;并比较了RNGk-ε紊流模型、标准k-ε流模型与物理模型试验的结果.结果表明,自由射流区轴向流速、表面冲击区轴向流速、表面射流区径向流速随自由水面隆起高度的变化规律符合正态分布,射流喷口中心线轴向流速符合半无限域衰减规律.与标准k-ε试验结果相比,RNGk-ε流模型更适合于浅水纯射流.

For studying the characteristics of jet in shallow water, the velocity distribution formulas of the vertical pure round jet in shallow water were proposed. When the free flow surface was tracked applying the volume of fluid （VOF） method, renormalization group （RNG） kinetic energy and dissipation rate （k-ε） turbulent model was adopted, and a vertical pure round single-hole jet was simulated in still and uniformity shallow water. After the free surface position and velocity field distributions of different areas were researched, the data of RNG k-ε turbulent model, standard k-ε turbulent model and the physical experimental model were compared. Results show that three variations of radial velocity distributions in free-surface jet area, axial velocity distributions in free jet area and in surface impinging area with water-surface elevation accord with normal distribution, and that axial velocity distribution of jet spout centerline accords with attenuation rate of half space. The RNG k-ε turbulent model is more suitable for pure jet in shallow water than standard k-ε turbulent model.