| Advance of freshet analysis is one of key measures of preventing or controlling flood, which have been widely applied on urban flood proofing, basin planning and engineering construction. Even through the theory have been developed at 70s last century, there are still many obstacle on practice use. On practical application of Advance of freshet analysis, experience is playing a very important role. The parameters of flood hydraulic simulation include boundary slates, lateral inflow, manning roughness coefficient, etc. Those parameters determine the reliability of flood simulation. However, some open-channel parameters lack exact values due to not having definitive measurement or not rendering a "properly-posed" system of equations in the formulation of their inverse problems. Calibration has been an integral part of flood modeling since its first emergence in late 1950s as a design and decision-making tool. Later research works determined that calibration is a "inverse problem". Inverse analysis of friction parameters for complex channels is discussed detailedly in the paper, before this, how to modeling basin flood is studied too.1. Study on basin food modeling: based on the character of basin flood, a new flood simulation system is provided, which include 4 kinds of component: node, element, boundary and load. The technology of coupling component and elements is discussed in detail. The stiffness matrixes of Pressmann weighted implicit four- point scheme, Muskingum-Cunge routing model, bank model and broad-crested weir are deduced in new system, which can represent hydraulic model, hydrology model, etc, and almost all types of flood simulation can be abstracted into the new system.2. Object oriented analysis is an important software development technology. In the paper, the frame of basin flood simulation software is constructed with the technology. By this frame, programmers can develop systems with the element components and load components according the interface protocol easily without comprehend whole system.3. Study on how to translate 1-D Saint-Venant unsteady flow equation into ODE format. Gremer and Yu provide an ODE format to solve Saint-Venant equation, but it produces natively error at the same time, multiplying a revision factor can improve its accuracy effectively.4. An integrated research frame of open-channel friction parameters is provided. The inverse analysis of open-channel friction parameters includes existence of solution, uniqueness of solution parameter identifiability, algorithm of solver, stability and evaluation of solution. This paper can acquaint readers with the progress and status about this inversion problem.5. Identifiability of open-channel friction parameters can be analyzed by theory of cybernetics, but we should transform Saint-Venant unsteady flow equation to ordinary differential equation. At most condition, the solution is not unique, and the BG theory can be applied to analyze resolution and variance of parameters6. According to theory of cybernetics, data, model and criterion are essentials of channel friction parameters inverse analysis. On the basis of error origins, three kind of object function are put forward: 1) object function which only embodying water levers; 2) object function which onlyembodying flood flows; 3) object function which embodying both water levers and flood flows;7. Variable metric algorithm is a familiar optimize method, but numerical studies on inversion of channel friction parameters show that the method's performance is not satisfactory. Utilizing generalized inverse matrix theory can make for the search orientation of optimize, which will improve efficiency greatly. During the compute, when Wiggins method is integrated into optimize algorithm, noise can be suppressed effectively, but damping least-squares method procedure's computational stability and resolution requiremen can't be satisfactorily met.8. A channel friction parameter inversion method based on kalman filter with unknown parameter vector is p...
|
PDF Full Text Request