关键词: 泥石流, 主河, 交汇, MAC法, 数值模拟

Abstract: To study the mechanism of confluence between debris flow and the main river，based on the theory of Newtonian and non-Newtonian fluid dynamics,the theoretical equation to describe the movement of debris flow in the confluence was established，and three-dimensional simulate model was also put forward，which includes numerical calculation method，the rheologic equation and the sediment deposit and transportation in a conjunction area．The calculation shows that this method is really feasible for an alysis of the distribution of sediment density and the change of water level，the calculation results are in good agreement with the model test data．

Key words: debris flow, main river, confluence, MAC method, numerical simulation