上下游初始水深比对溃坝水流传播的影响
Effects of Initial Water Depth Ratio of Upstream and Downstream on Dam-break Flow Propagation
作者：刘文军(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065)；王波(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065)；张建民(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065)；陈云良(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065)；伍超(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065)；刘鑫(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065)；宋家俊(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065)
Author：LIU Wenjun(State Key Lab. of Hydraulics and Mountain River Eng., Sichuan Univ., Chengdu 610065, China)；WANG Bo(State Key Lab. of Hydraulics and Mountain River Eng., Sichuan Univ., Chengdu 610065, China)；ZHANG Jianmin(State Key Lab. of Hydraulics and Mountain River Eng., Sichuan Univ., Chengdu 610065, China)；CHEN Yunliang(State Key Lab. of Hydraulics and Mountain River Eng., Sichuan Univ., Chengdu 610065, China)；WU Chao(State Key Lab. of Hydraulics and Mountain River Eng., Sichuan Univ., Chengdu 610065, China)；LIU Xin(State Key Lab. of Hydraulics and Mountain River Eng., Sichuan Univ., Chengdu 610065, China)；SONG Jiajun(State Key Lab. of Hydraulics and Mountain River Eng., Sichuan Univ., Chengdu 610065, China)
收稿日期：2018-04-03 年卷（期）页码：2019,51(2):121-129
期刊名称：工程科学与技术
Journal Name：Advanced Engineering Sciences
关键字：溃坝水流;初始水深比;水力特性;额外负波;波速
Key words：dam-break flow;initial water depth ratio;hydraulic characteristics;extra negative wave;wave velocity
基金项目：国家重点研发计划资助项目（2016YFC0401707）；四川省青年科技创新研究团队专项计划资助（2016TD0020）
中文摘要
溃坝水流的传播很大程度上受着上下游初始水深比的影响，过去对溃坝洪水的试验研究很少涉及到上下游初始水深比大于0.5时的情形，大部分研究的系列性不足且较少关注洪水波在上游库区中的运动。作者在一个大尺度水槽（长18 m、宽1 m、高1.09 m）中，通过波高仪的测量手段对上下游初始水深比0～0.9范围内的大坝瞬溃洪水进行了大量实验，获取了许多新发现。研究结果表明：当下游无水时，溃坝水流波前区域的水深会出现明显的雍高，波前运动速度也明显低于Ritter解；当上下游初始水深比大于等于0.3时，溃坝水流演进一段时间后，在靠近闸门处会出现以波浪形式向库区演进的额外负波，该负波不同于以往研究中定义的与上游静水区衔接的负波；当上下游初始水深比大于等于0.5时，溃坝水流运动的稳态区会出现明显的波动，水流以波浪形式向下游演进，其中第1个出现的波浪波峰高度最高且在演进的过程中基本维持高度不变，但产生的这些波浪数量有限，波浪演进过后的断面水深会逐渐恢复稳定，且稳定后的水深与Stoker解符合较好。在试验观测到的范围内，同一水深比时，与上游静水区衔接的负波波速在演进的过程中不断降低至稳定值，而第1个出现的额外负波波速不断增加；下游波前的演进速度基本维持不变，而下游第1个出现的波浪波速会增加；另外，随着水深比的增加，第1个出现的额外负波波速变大，而下游第1个出现的波浪波速变小。从两组不同上游水深在同一水深比时各水力要素的对比情况中发现瞬时溃坝水流的运动在湿底情况下依然具有很好的相似性。
英文摘要
Water depth ratio between upstream and downstream plays an important role on dam-break flow. In the past studies, few researches were conducted when the water depth ratio was greater than 0.5, and most of the studies didn't have enough series and discussed little about the upstream reservoir. In this paper, an experimental study was conducted by using wave probe on a large scale flume (length 18 m, width 1 m, height 1.09 m) for the instantaneous dam-break flow at the initial water depth ratio of 0 to 0.9, and new phenomena have been found. The experiment found that when downstream is dry, the water depth in the wavefront area of the dam-breaking flow will have a significant raise, and the wavefront velocity will be obvious lower than the Ritter's solution. When the water depth ratio is greater than 0.3, extra negative waves will appear near the gate after a period of time, and these waves have different characteristics compared to negative wave linked to the upstream hydrostatic area. When the water depth ratio is greater than 0.5, waves appears in the downstream which cannot be considered as steady. Among them, the first wave peak is the highest and remains almost unchanged during the evolution. However, these waves have a trend to return stable and the stable water depth has a good agreement with Stoker's solution. Within the experimentally observed range, the average velocity of the first extra negative wave increases under the same water depth ratio, as well as the first wave in the downstream. In addition, as the water depth ratio increases, the average velocity of the first extra negative wave becomes larger, while the first wave in the downstream decreases. It is found that the characteristic of instantaneous dam-break flow is very similar through the comparison of various hydraulic factors between different upstream headwater but in same initial water depth ratio.
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