海底滑坡海啸的颗粒流耦合模型

Granular flow coupling model for tsunami generated by submarine landslide

海底滑坡的运动可能引发海啸,破坏离岸设施,威胁海岸带安全。国内外关于海底滑坡引发海啸的研究方兴未艾。采用Mih颗粒流模型控制具弱黏聚力的砂土滑坡运动,利用两相流模型计算岩土体-水体相互作用及RNG湍流模型控制水体运动,构建了基于颗粒流模型的海底滑坡海啸全耦合数值分析方法。通过简单水槽水下滑坡案例进行了海底滑坡海啸全过程研究。数值分析再现了变形滑体的不均一运动、密度分异流动、水滑机制和以波谷为典型特征的涌浪波等典型海底滑坡及海啸现象,这表明数值模型具有有效性。许多海域(包括中国南海北部)都存在弱黏聚力和无黏聚力的水下滑坡,该数值方法值得推广和进一步研究完善。

The motion of submarine landslide might generate tsunami, destroy the offshore facilities and threatening the safety of coastal zone. At present, the research on submarine landslide generated tsunami is in the ascendant. Mih granular flow model is adopted to control the movement of sandy landslide with low cohesive. Two-phase model is used to calculate the interaction of soil/water. RNG model is applied to control the dynamic of water. Based on granular flow model, the coupling numerical analysis method of submarine landslide tsunami is established. This full coupling model can be more accurate to characterize the movement of slide, the interaction between the sliding mass and the water, and the following impulse wave process of generation, propagation, and run-up. The case of simple submarine landslide in water tank is used to study the whole process of submarine landslide and the following tsunami. Numerical analysis presents the inhomogeneous dynamic of deformable slide mass, the differentiation flow of density, the hydroplaning mechanism, the impulse wave characterized by trough, and such typical phenomena of submarine landslide and tsunami are generated. These mean the numerical model built is valid. Low and non-cohesive submarine landslide exist in many sea regions（including north of the South Sea, China）. Therefore, this numerical method is worth spreading and making further research and improvement.