横流中射流的旋涡结构研究

In this project the vortex structures of single circular and slot jets in cross-flow is analysed by using PIV to measure the flow field in flume. The k-ε turbulence model and Hybrid Finite Analysis Method are also applied to simulate the 3-D flow field. For the geometry characteristics of jets, it is found that the jet trajectory and spreading width of jet are effected strongly by the velocity ratio (jet velocity to cross-flow velocity, and its relationship is given. An important discovery is obtained that the maximum height of slot jets decreases along transversal from the center line to two sides. And the relationship of this phenomenon is given also.. For the complex 3-D flow field of the jets in cross-flow, the shear.layer vortexes in the up- and down-stream interfaces between the jet and cross-flow are found out and its instability is discussed. There are the horseshoe vortex systems around the jet orifice. A pair of separative vortex is formed on the two sides of jet and is merged into.the jet body in the far field to form the counter-rotating vortex pair (CVP) of jet. Through topological theory and principle on flow analysis,draw out the topological characteristic of near field of jets..

污染物通过扩散器排入河流、近海，其流动形态可概化为横流中的射流。其流动形态中存在大尺度的旋涡结构，它影响着污染物的浓度分布。本项目拟采用试验方法对横流中单孔射流的脱落旋涡和线射流的端涡结构及其对射流主体的影响进行研究。这将在旋涡动力学方面有一定学术价值，对扩散器水力设计也有重要的参考价值。