摘要
坝体溃决后大量库水会在短时间内下泄形成溃坝洪水,会对下游结构物安全存在巨大威胁。本文基于RNG k-ε湍流模型对三维溃坝洪水的演进及溃坝波与下游坝体的相互作用开展系统数值研究,主要讨论了溃坝波的演进规律、下游垂直坝体处冲击压强随时间的变化和分布规律,以及上下游不同水深比α对冲击峰值压强的影响。研究表明:溃坝波在演进时会导致下游水面线峰值呈现一个先增加随后坦化的趋势,随后受到下游坝体壁面的影响,溃坝波接触壁面后发生壅水,波高迅速增加。上下游水深比α=0.3时,其下泄洪水波的相对峰值达到最大值。随后随着水深比增大,其溃坝波传播速度和各监测点水位峰值均减小;瞬时冲击压强值随着水深比α增大而减小且与第一次冲击后最大压强值的比值减小。造成下游坝体上部分测点的压强主要为静水压强,下部分测点压强则主要是冲击压强和静水压强;垂直方向的峰值压强分布呈现先减小再变大再减小的趋势而水平方向呈对称分布,且最大冲击压强出现在下游水深之上的第一个点,由冲击压强产生。
The release of a large amount of water within a short period of time after dam breaking,forms the dam-break flood and poses a threat to the safety of downstream structures and buildings.In the present study,a systematic numerical study is carried out to investigate the propagation of the dam-break wave and the impact pressure based on the RNG k-εmodel.The evolution process of the dam-break waves and the impact pressure of the downstream panel versus time are explored.Furthermore,the influences of different ratiosαof upstream water depth to downstream water depth on the peak of impact pressure are investigated.The results indicate that the dam-break waves during its evolution will lead to a trend of increasing and then flattening the peak of the downstream water surface line.Afterward,due to the influence of the downstream dam wall,the dam-break waves become congested when the dam-break wave touches the wall and the wave height will increase rapidly.The relative peak value of the downstream flood wave reaches its maximum value when the ratio of the upstream water depth to downstream water depth is equal to 0.3 orα=0.3.With the increase of the ratioα,the propagation velocity of the dam-break wave and the maximum water level at each monitoring point decrease.In addition,the value of instantaneous impact pressure also decreases with the increase of the ratioα,and the ratio of the instantaneous impact pressure to the maximum pressure value decreases after the first impact,which is attributed to the fact that the pressure at the upper part of the downstream dam is the hydrostatic pressure,while the pressure at the lower part mainly depends both on dynamic pressure and hydrostatic pressure.Moreover,the distribution of peak pressure in the vertical direction decreases first,then increases,and finally increases,while the horizontal direction is symmetrically distributed.The maximum shock pressure appears at the first point above the downstream water depth,which is generated by the dynamic impact pressure.
作者
周昔东
何小泷
袁浩
孙倩
ZHOU Xidong;HE Xiaolong;YUAN Hao;SUN Qian(School of River and Ocean Engineering,Chongqing Jiaotong University,Chongqing 400074,China;Chongqing Southwest Research Institute for Water Transport Engineering,Chongqing Jiaotong University,Chongqing 400016,China;School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China)
出处
《中国水利水电科学研究院学报（中英文）》
北大核心
2023年第1期74-82,共9页
Journal of China Institute of Water Resources and Hydropower Research
基金
重庆市研究生联合培养基地建设项目资助(JDLHPYJD2018001)。
关键词
溃坝洪水
数值模拟
水深比
演进规律
冲击压强
dam-break flood
numerical simulation
water depth ratios
evolutionary rule
impact pressure
