立轴旋涡的环量分析

环量是形成立轴旋涡的主要影响因素,对环量进行定量分析,有助于进一步了解旋涡的生成规律和消除原因,目前这方面的研究成果不多。某工程溢洪道进口试验产生立轴旋涡,导致水位抬高,不能满足泄洪要求,通过设置防涡墩消除了旋涡;对这有无防涡墩两种情况进行数值模拟,分析环量的变化规律,计算和试验较为吻合。结果表明:串通旋涡稳定后,水面的环量随积分曲线半径增大而增大,水气交界面的环量则随高程降低而减小;旋涡形成过程中水面的环量逐渐增大,旋涡稳定后环量也基本不变;防涡墩的存在阻碍水流旋转,使得环量大幅度降低,可有效地消除立轴旋涡。

Circulation analysis of vertical vortex

The circulation is the main factor of vertical vortex formation.With the quantitative analysis of the circulation,the generating regularity and eliminating reason of the vortex can be further learned.Model investigations show that the vortex occurs at the spillway intake which leads to raise the water level,cannot meet the demand of the flood discharge.By setting anti-swirl piers,the vortex is eliminated.The two cases are simulated and the circulation regularities are analyzed,the computed results are in agreement with the measured data.It is shown that while the vortex is stable,the circulation of the water surface increases with the increase of the integral radius,and the circulation of water-air interface decreases with the decrease of the elevation.The circulation increases in the process of the vortex generation and varies very little while the vortex is penetrated and it reduces largely with the setting of anti-swirl piers.