用VOF方法模拟静止浅水环境中的垂向紊动射流

Simulation of a vertical turbulent jet discharged from the bottom of static shallow water with the VOF method

以k ε紊流模型为基础,针对浅水环境垂向射流的水面会有明显突起情况,采用VOF(VolumeofFluid)方法追踪自由面,建立了适合浅水环境垂向平面紊动射流的二维数学模型。对不同入射速度、水深、入射口宽度组合进行了大量的数值模拟实验,对整个流场的分布作了分析,发现自由面的分布特点和速度矢量场的分布特点相对应;中轴线附近的自由面隆起具有自相似性,文中给出了拟合表达式;由于水面的阻滞,中轴线上垂向速度的衰减较自由射流快,衰减规律随水深和射流宽度而异。

Based on the universal k-ε turbulent model, we trace free surface with the volume of fluid (VOF) method for taking the character of distinct surface elevation, and establish a two-dimensional model of vertical plane turbulent jet discharged from bottom of shallow water. Many numerical simulation experiments are implemented for differential groups of water depth, velocity and width of jets and the whole flow field is analyzed. We find that the distribution characters of velocity vector field and that of surface elevation are corresponding. A self-preservation law of surface elevation distribution around jet axis is found and an empirical formula is established. Due to the surface retardation, the attenuation rate of velocity becomes quicker, which depends on water depth and jet width.