| The plain reservoir is a type of hydraulic project which is built to regulate water resources.With the construction of South-to-North Water Diversion Project,a number of large plain reservoirs,such as Datun Reservoir,have been built and put into operation,and the project scale shows a tendency of growth.Plain reservoirs are mostly built near densely populated areas,so it is vital to ensure the safety of people's lives and properties by maintaining the normal operation.The plain reservoir has a large area and perimeter,which means a slight increase in the height of the dam will lead to a significant rise of the project scale,so it is necessary to determine a proper and balanced design wave height to ensure both the safety of the project and the reduction of the cost.Therefore,the wave height calculation becomes a crucial part in the design of the cofferdam..Furthermore,after the project is completed,the cofferdam will suffer constant scour under wave action,so study on the wave height in plain reservoirs is of great significance for the maintenance and management of reservoirs.Study on wave height in plain reservoirs comprises two aspects,the probability distributions of wave height and the calculations of characteristic values of wave height.They represent the rules and characteristics of wave height in different directions and both of them are indispensable for project design and maintenance management.At present,the research on probability distribution of wave height is mainly focused on the ocean,while that in plain reservoirs is quite rare.Although the calculation formulas for characteristic values of wave height are widely used in engineering design,none of those is special for plain reservoirs.Accordingly,in this paper,the probability distributions of wave height in shallow water of the plain reservoir were studied in the following aspects.(1)Wave height distribution of Maximum Entropy in the plain reservoir as well as its parameter estimation.The Distribution of Maximum Entropy(DOME)which has a distinct superiority was selected among the commonly used probability distributions of wave height,and the estimation methods of the four unknown parameters in it was analyzed.The feasibility of the parameter estimation results was verified by K-S test,and the fitting effects between the wave height data and the DOME obtained by different parameter estimation methods were compared,using the sum of squares of deviations,mean square error and maximum error.Afterwards,the DOME and the optimum parameter estimation method were applied to a concrete case,the result showed its fitting error is smaller than that of other commonly used distributions.(2)DOME statistical model of wave height in shallow water.The parameter estimation program,hypothesis test program and error computation program for the four parameter estimation methods of DOME in MATLAB were combined to establish the DOME statistical model of wave height in shallow water.It was then used in the calculation for the probability distribution of wave height data at a certain speed of wind,and the result was tested to be feasible by K-S test.(3)Application of DOME statistical model in Datun Reservoir.The DOME statistical model of wave height was applied to Datun Reservoir,a plain reservoir of South-to-North Water Diversion Project,and the distributions of Maximum Entropy of wave height at different wave speed were acquired.Afterwards,the characteristic wave height at different wind speed was calculated by the obtained distributions.In the last,the calculation formula for characteristic wave height applying to Datun Reservoir was deduced by the fitting between wind velocity and characteristic wave height according to the structure of representative formulas for characteristic wave height. |
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