45°弯段明渠剪切分层流稳定性分析试验研究  

Experimental investigation on stability of stratified shear flows in open channel with a bending angle of 45°

作　　者：褚克坚[1] 华祖林[1] 王惠民[1] 邢领航[1] 

机构地区：[1]河海大学环境科学与工程学院,江苏南京210098

出　　处：《河海大学学报（自然科学版）》2004年第6期640-643,共4页Journal of Hohai University(Natural Sciences)

基　　金：国家自然科学基金资助项目(50009001);江苏省自然科学基金资助项目(BK2000004)

摘　　要：通过物理模型试验,对45°弯段明渠剪切分层流的稳定性进行研究,同时进行了直道和45°弯段两种水槽的分层流试验,获得不同工况下的断面流速、温度、紊动动能、雷诺应力等物理量.选用初始密度弗汝德数作为稳定性判数,对直道和45°弯段水槽的分层流稳定性进行了分析,得出试验条件下两种水槽的稳定性判别标准并进行对比.结果表明,45°弯段分层流稳定分层的临界初始密度弗汝德数值约为直道分层流的0 7倍,说明弯段的存在加剧了分层流的垂向掺混.Laboratory experiments were performed in two flumes, a straight one and a weakly curved one with a bending angle of 45°, for study of the stability of thermally stratified shear flows. Some hydraulic parameters in different cases, such as the flow velocity, temperature, turbulence energy, and Reynold stress, were obtained. With the initial densimetric Froude number taken as the index for reflection of the stability of the stratified shear flows, the stability criterion for the flows in the two flumes was derived under the experimental condition. The comparison of the stratified flows in the two flumes indicates that the critical initial densimetric Froude number for stable stratification in the weakly curved flume is about 0.7 times of that in the straight one, showing that the bending section intensifies the mixing of stratified flows in vertical direction.

关 键 词：明渠 断面流速 紊动 水槽 物理模型试验 雷诺应力 判别标准 分层流 临界 动能 

分 类 号：TV133[水利工程—水力学及河流动力学] O359[理学—流体力学]