射流形状对水垫塘底板冲击动压特性的影响

高坝工程坝身泄洪水流对下游水垫塘底板的冲击动压是水垫塘底板失稳破坏的重要因素。通过物理模型试 验的方法详细分析了斜向淹没冲击射流形状( 射流长度与宽度之比) 对水垫塘底板的冲击动压分布特性影响, 结果 表明: 随着射流长宽比的增加, 射流入水形状由宽扁形横向扩散入水转变为窄长形纵向扩散入水, 水垫塘底板上的 冲击动压和脉动压强先增大后减小。同时, 上游水位及下游水垫深度对冲击动压值及分布也存在较大影响, 冲击动 压值随上游水位增加而增大, 随下游水深增加而减小。 The impact pr essure o n the plunge po ol bot tom caused by the flow discharg e o f high dam is a key facto r to lead to the instability of the plung e pool. I n this paper , the eff ects of the submerg ed jet f low shape ( aspect ratio of jet flow leng th and width) o n the impact pressur e distr ibut ion in the plung e po ol bo ttom w ere inv estigated based on the physical model tests. T he results showed that w ith the incr easing of aspect rat io, the shape of jet flow var ies f rom the wide2flat shape w ith hor izontal dif2 fusion to the long2narr ow shape w ith v ertical diffusio n, and t he impact pressure and fluctuating pr essure on the plung e poo l bo t2 tom increase first and then decrease. In additio n, the upstr eam w ater lev el and dow nst ream w ater depth hav e g reat effects on the impact pressure in the plunge po ol bottom, and the fluctuating pressur e increases w ith the increasing of upstream water level but decreases with t he increasing of dow nstr eam w ater depth. 国家自然科学基金青年科学基金项目( 50909067; 51009102; 51179113) ; 新世纪优秀人才支持计划( 2011SCU2NCET21020589)