A Two-phase Debris Flow Model With Boulder Transport
A Two-phase Debris Flow Model With Boulder Transport
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含巨石输送的两相泥石流模型
DOI：
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发表时间：
2011
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通讯作者：
F. Miralles
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作者：
C. Martinez;R. García;F. Miralles
本文提出了一个模拟泥石流的准三维数值模型，该模型考虑了水和细颗粒物的连续非牛顿流体相和大颗粒物（如卵石）的非连续相。粒子处理的拉格朗日参考框架使用三维离散元法。流体相在RiverFLO-2D模型中实现，该模型在三角形非结构网格上用有限元法求解2D深度平均浅水方程。该模型考虑了颗粒与颗粒和壁面与颗粒的碰撞，同时考虑到颗粒浸没在流体中并受到重力、摩擦力和拖曳力的影响。Bingham和Cross流变模型用于连续相，提供非常稳定的结果，即使在非常低的剪切速率范围内。结果表明，宾汉公式能更好地模拟低切应力时流体的停止。数值结果与解析解和水槽实验数据的比较表明，该模型能够再现大颗粒在水流中的运动。应用程序来模拟发生在北方委内瑞拉在1999年的泥石流表明，该模型可以复制的主要巨石堆积报告的事件。孤石堆积，泥石流，离散元法，有限元法，拉格朗日列式语言：en
We present a quasi three-dimensional numerical model to simulate debris flows that considers a con-tinuum non-Newtonian fluid phase for water and fine sediments, and a non-continuum phase for large particles such as boulders. Particles are treated in a Lagrangian frame of reference using the 3D Discrete Element Method. The fluid phase is implemented in the RiverFLO-2D model, which solves the 2D depth-averaged shallow water equations with the Finite Element Method on a triangular non-structured mesh. The model considers particle-particle and wall-particle collisions, taking into account that particles are immersed in a fluid and subject to gravity, friction and drag forces. Bingham and Cross rheological models are used for the continuum phase providing very stable results, even in the range of very low shear rates. RESULTS show that Bingham formulation proves better able to simulate the stopping of the fluid when the applied shear stresses are low. Comparing numerical results with analytical solutions and data from flume-experiments demonstrates that the model is capable of replicating the motion of large particles moving in the fluid flow. An application to simulate debris flows that occurred in Northern Venezuela in 1999 shows that the model can replicate the main boulder accumulation reported for that event. Keywords boulder accumulation, debris flow, discrete element method, finite element method, Lagrang-ian formulation Language: en