Study on Local Extremum Diminishing Scheme Applied to 2D Depth-averaged Model

• Main Authors: Lo, Chi-Wen, 羅琦雯
• Other Authors: Yang, Jinn-Chuang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/95575429777777519255

碩士 === 國立交通大學 === 土木工程學系 === 98 === The purpose of this study is to use the Local Extremum Diminishing (LED) scheme integrated with finite volume method and Runge-Kutta time stepping method for solving 2D depth-averaged equations. The LED scheme preserves the properties of that the local maxima would not increase and the local minima would not decrease to restrain the numerical oscillation efficiently. Meanwhile, the fourth order Runge-Kutta method is also adopted in time difference term to improve the numerical stability. In this study, the dam-break flow, the transcritical flow with hump and the cross-wave flow with contraction are simulated to discuss the accuracy affected from inertia force term, gravity force term and bed friction term in the governing equations receptively. Furthermore, the proposed model is also applied to the practical field simulation of Tung-Pu-Ruei creek. The discussions for the exponent β of coefficient of artificial viscosity with cross-wave simulation are presented. The sensitivity analysis of β is analyzed by using Coefficient of Efficiency (CE), Root-Mean-Square Error (RMSE), and Error for the Peak Value (EVP), which are analyzed on the basis of comparing the simulation and experimental data. By comparing with analytic solution and experimental data, the computed results from proposed model with LED scheme can provide adequate accuracy. In addition, for the practical application of Tung-Pu-Ruei creek, the LED scheme can also handle the complex flow.