工程科学与技术2025，Vol.57Issue(6)：18-26,9.DOI:10.12454/j.jsuese.202400060
湿床溃坝波演进特性试验研究
Experimental Study of Wet-bed Dam Break Wave Evolution Properties
摘要
Abstract
Objective The propagation of dam-break flow is significantly influenced by both upstream and downstream initial water depths,while the effect of slopes on flow propagation should not be overlooked.It is recognized that numerical simulations still have limitations in accurately modeling large-scale and large-deformation water surface phenomena.In addition,on-site observations of dam-break flow remain limited due to spatial and temporal constraints.Dam-break experiments allow visualization of the evolution of dam-break waves,wall impact pressure,and other related dy-namics.Therefore,experimental studies of dam-break flows are of great importance compared to numerical simulations.However,few existing experimental studies simultaneously investigate the influence of water depths and slopes on the spatiotemporal evolution of dam-break wave re-gimes and heights. Methods Accordingly,an experimental investigation was conducted to examine the evolution characteristics of wave regimes and wave heights resulting from a wet-bed dam break.A large-scale flume measuring 52 m in length,1.2 m in width,and 1 m in height was utilized,which was di-vided into two sections by a 10 mm thick fiberglass board positioned 12 m from the inlet.The upstream water was released by lifting the fiber-glass board connected to an electric motor and controlled by a computer program to minimize experimental errors.The flume bottom and sides were made of toughened glass,which facilitated the observation of the experimental process while maintaining the accuracy of the detected water surface.The slope of the flume bed was adjusted using 13 pairs of hydraulically operated lifting columns that were automatically controlled with high precision.Various combinations of upstream water depth hp(hp=0.5,0.6,0.7,and 0.8 m),downstream water depth hd(hd=0.1,0.2,0.3,and 0.4 m),and slopes i(i=0,2‰,4‰,and 6‰)were considered to evaluate their effects on the dam-break waves,resulting in a total of 64 sce-narios.The spatiotemporal evolution of the dam-break waves was measured using ten wave gauges positioned at different downstream locations. Results and Discussions The experimental results showed that the regimes of the dam-break waves were strongly influenced by both the up-stream and downstream water depths as well as by the slopes.The regimes of the dam-break waves were distinguished using the global Froude number(Fx).Specifically,when Fx was less than 1.2,the wave propagation resembled that of an undular wave,whereas when Fx was greater than 1.2,it exhibited characteristics similar to a bore wave.In addition,the rise pattern of the dam-break flood level was significantly affected by the global Froude number Fx.Based on the variation of the experimental data,a flood-level rise model for the increase of the dam-break flood level ΔH with time T for different values of Fx was proposed.The root mean square error between this flood-level rise model and the results of existing studies was 1.7%,indicating that the proposed model accurately predicted the water-level rise for the dam-break flood.In addition,the relation-ship between the dimensionless water-level rise velocity(C)and the global Froude number Fx was investigated for two different waveforms.The value of C increased as Fx increased when Fx was less than 1.2 and remained constant as Fx increased when Fx was greater than 1.2.This study also examined the applicability of the Stoker solution in predicting wave heights by comparing the experimental data with the Stoker theoretical results.The findings demonstrated that when the dam-break wave propagated as a bore wave,the maximum relative error between the Stoker theoretical solution and the experimental data was 5.97%,indicating that the Stoker solution exhibited minimal error in determining the wave height under the bore wave condition.However,when the dam-break wave propagated as an undular wave,the maximum relative error between the theoretical Stoker solution and the experimental data reached 23.63%,indicating that the Stoker solution has a larger error in estimating the wave height under the undular wave condition.Formulae for calculating the maximum wave height hmax and Fx under different upstream and downstream water depth ratios α(α=hd/hp)were established to enable more accurate prediction of the variation in maximum wave height,consid-ering the influence of slopes and different upstream and downstream water depths.The calculation method presented above was compared to ex-isting experimental data and showed satisfactory agreement. Conclusions The varying water depths upstream and downstream contribute to the propagation of dam-break waves in two distinct forms,distin-guishable by the proposed global Froude number.The phenomenon is characterized as follows:when Fx is less than 1.2,the wave manifests as an undular wave,whereas when Fx exceeds 1.2,it transforms into a bore wave.In the case of undular waves,the rate of water level rise increases proportionally with Fx,while in bore waves,this rate remains relatively constant.Based on the influence of Fx on the dam-break wave surface,a functional relationship was established between the rise in flood levels after a dam break and Fx.It was observed that when the dam-break wave propagates as an undular wave,the initial wave height represents the peak height.The experimental data also indicate that the ratio(hmax‒h1)/hp decreases linearly with increasing Fx values(h1 is the wave height according to the Stoker theory solution).In addition,a formula for calculating the maximum wave height was derived by integrating this finding with the Stoker solution.The results contribute significantly to a comprehen-sive understanding of the formation and evolution of dam-break flood waves,providing a theoretical foundation for establishing dam-break flood hazard science.关键词
湿床/全局弗劳德数/溃坝波形/洪水位爬升/最大波高Key words
wet-bed/global Froude number/wave regime/flood level rise/maximum wave height分类
建筑与水利引用本文复制引用
周昔东,袁浩,苏立君,胡瑞昌,孙倩..湿床溃坝波演进特性试验研究[J].工程科学与技术,2025,57(6):18-26,9.基金项目
国家重点研发计划项目(2022YFC3800500) （2022YFC3800500）
重庆市技术创新与应用发展专项重点项目(CSTB2023TIAD‒KPX0073) （CSTB2023TIAD‒KPX0073）
重庆市研究生联合培养基地项目(JDLHPYJD2019001) （JDLHPYJD2019001）
