Applying NewC Scheme And Adjoint State Method to Parameter Identification of 1D Open-Channel Flow
Date Issued
2007
Date
2007
Author(s)
Yang, Tsung-Han
DOI
zh-TW
Abstract
Using a hydrodynamic numerical model that solves De Saint-Vanent equations for one-dimension free-surface flow often encounters acutely numerical vibration in transcritical flow that is between supercritical and subcritical flow causing model to be unstable. In this research, citing NewC scheme which could simulate the unsteady transcritical flow without numerical instability. NewC scheme applies staggered grids, finite difference method, and reduction of convective acceleration to solve the tri-diagonal coefficient matrix of discharge with boundary conditions on each end, then transfer to water level. NewC scheme take advantage of stability, high efficiency, and doesn’t have to compute Frouds number.
Applying numerical model to simulate the unsteady flow would always meet the error between computing result and observation because of uncertainties about initial condition, boundary condition or minor loss of Manning roughness coefficient. The error would grow with time increasing. In this research, we assume that there is only parameter uncertainty in model, then derive the adjoint state equations and use the minimum sum of error square to identify the parameters of model.
We use two set of numerical result to be the observation data, then take 11 set of observing system simulating experiments by using adjoint state method, Newton’s method, and quasi-Newton’s method to compare and discuss the results of parameter identification.
Subjects
NewC法
跨臨界流
變量流
伴隨狀態法
參數檢定
NewC scheme
transcritical flow
unsteady flow
adjoint state method
parameter identification
Type
thesis