水平圆形浮力射流稳定性及混合特性研究

Stability and mixed characters of horizontal round buoyant jets in quiescent shallow water

在对静止环境中有限水深水平圆形热浮力射流进行数值计算的基础上,对不同射流和环境条件下的两种流动类型:热水以浮力表面层形式向下游扩散的稳定排放和浮力热水与环境水体发生二次挟带的非稳定排放的判据进行了验证,并对流动的稀释度特性进行了研究.认为在稳定排放条件下,浮力热水在近区快速地被稀释,近区局部水温较高;而非稳定排放条件下,近区局部水温较低,浮力热水向下游的影响范围较广;给出了稳定和非稳定排放下的表面最小稀释度公式;最后拟合出了表面碰撞区中心点位置的公式,为流动区域划分提供了量化依据.

On the basis of the numerical calculation of the 3-D round heated buoyant jets discharged from a horizontally submerged port in quiescent shallow water, the stability criterion for two generic flow patterns with different jet discharge and environmental parameters, a stable buoyant flow discharge with the mixed warm fluid leaving the near field in a surface warm water layer and an unstable buoyant flow discharge with re-entrainment of warm water in the near field, were numerically demonstrated. The results showed that the stability criterion was in excellent agreement with experiments, and its mixed characters were also numerically predicted. Under stable discharge, the thermal buoyant jets could be diluted rapidly, and the temperature in the near field is high. The formulas were given out for the minimal surface dilution under stable and unstable discharge, and the effects of the dens metric Froude number to the minimal surface dilution were inconspicuousness under unstable discharge. Furthermore, the formulas of the center point of the surface impingement region were presented to give quantify reference to the flow region definition.