NUMERICAL SIMULATION OF SUBAQUEOUS LANDSLIDE BASED ON OPENFOAM AND PFC COUPLING METHOD
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摘要: 水下滑坡是常见的地质灾害之一,为解决离散元PFC难以模拟水下流体环境的问题,提出采用计算流体力学OpenFOAM与离散元PFC耦合的计算方法。针对流固耦合中的尺度相似性问题,提出了适用于该耦合方法的相似性方法并验证了其可行性。通过典型案例分析了基于该耦合方法的水下滑坡动力学特性及堆积形态,并与单向耦合水下滑坡和陆上滑坡结果进行了对比。结果表明该耦合方法能够较好地模拟水下滑坡运动规律,主要表现为滑坡体前端厚度较大并呈椭圆面;水下滑坡运动过程和堆积形态与陆上滑坡差异较大,OpenFOAM-PFC双向耦合与单向耦合方法相比具有优越性。Abstract: Subaqueous landslides are one of the common natural disasters. PFC is difficult to simulate the subaqueous fluid environment. In order to solve this problem, a calculation method using computational fluid dynamics OpenFOAM and PFC is proposed. Aiming at the problem of scale similarity in fluid-solid coupling, a similarity method suitable for this coupling method is proposed and its feasibility is verified. The dynamic characteristics and accumulation morphology of subaqueous landslides based on the coupling method are analyzed through typical cases, and compared with the results of unidirectional coupled subaqueous landslides and upland landslides. The results show that the coupling method can simulate the law of subaqueous landslide movement well, which mainly shows that the front end of the landslide body is thick and elliptical. Subaqueous landslide movement process and accumulation form are quite different from the landslides on land. The OpenFOAM-PFC bidirectional coupling method is superior to unidirectional coupling method.
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Key words:
- PFC /
- OpenFOAM /
- Fluid-solid coupling calculation /
- Subaqueous landslide
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表 1 相似性参数及验证结果
Table 1. Similarity parameters and results
土体颗粒半径/mm 放大倍数N 颗粒个数 颗粒总体积/cm3 颗粒平均速度/m·s-1 颗粒平均位移/m 颗粒运动时间/s 计算所需时间/s 1 0.2 125 000 523.6 0.6570 0.2780 0.5 37 689 1.75 0.35 23 324 523.6 0.6571 0.2781 0.5 654 2.5 0.5 8000 523.6 0.6571 0.2782 0.5 118 5 1 1000 523.6 0.6571 0.2782 0.5 17 10 2 125 523.6 0.6572 0.2783 0.5 8 50 10 1 523.6 0.6574 0.2786 0.5 6 表 2 计算模型细观力学参数
Table 2. The meso mechanical parameters of calculation model
细观模型 接触黏结模量/Pa 法向/切向刚度比 接触黏结强度/Pa 接触黏结张拉强度/Pa 摩擦系数 土体 8e7 3.0 1.4e5 2.0e5 0.4 -
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