Author(s): Joongcheol Paik; Sang-Deok Park; Young-Ho Yoon
Linked Author(s): Joongcheol Paik
Keywords: Debris flow; Mudflow; Shock capturing method; Flow resistance relations
Abstract: A numerical model that solves one-dimensional (1D) shallow water equations with flow resistance terms is developed to predict the time-dependent behavior of non-Newtonian mud/debris flow dynamics. Various relations, such as a simple Bingham plastic, TurbulentCoulomb-yield, immature debris and Voellmy debris flow formula, are incorporated into the model to determine the mud/debris flow resistance. A second-order-accurate finite volume method using a shock-capturing scheme with TVD limiters has been employed to solve the governing equations. The source terms are taken into account using the fractional-step approach. The performance of the numerical model and the grid sensitivity of the solutions are evaluated by comparing the numerical solutions computed on two refined grids with analytical solutions accounting for a Coulomb-type friction law on the dry bottom of the constant slope which is higher than the internal friction slope. Numerical tests confirm that the numerical model yields solutions in very good agreement with the analytical solutions even near the discontinuities at appropriately refined grid resolution. The numerical model is applied to simulate a mudflow experimentally investigated by instantaneously releasing a fixed volume of a fluid mixture from an upstream reservoir into a dry, constant slope, rectangular channel. The results show that the computation employing a simple Bingham plastic formula with experimental parameters without calibration reproduces the experimental measurements with overall good accuracy and underscores the potential of the model incorporated with various resistance relations to predict immature and mature debris flows.
Year: 2010