This paper presents a hybrid discrete bubble-lattice Boltzmann–discrete element modelling framework for simulating gas-charged sediments, especially in the seabed. A discrete bubble model proposed in chemical engineering is adapted in the coupled discrete element/lattice Boltzmann method to model the migration of gas bubbles in saturated sediments involving interactions between gas bubbles and fluid/solid phases. Surface tension is introduced into the discrete bubble model in this work, so that it can handle the complex gas–fluid–solid interface. The lattice Boltzmann and discrete element methods are, respectively, employed to simulate fluid flows and mechanical behaviours of sediments. A velocity interpolation-based immerse boundary method is utilised to resolve the coupling between the fluid flow and the solid/gas phase. The proposed technique is preliminarily validated using simulations of bubble migration in fluids, which is followed by high-resolution investigations of the transport of a gas bubble in seabed sediments. It is demonstrated that this hybrid method can reproduce, to a certain degree, the characters of bubbles moving in seabed sediment tests.

中文翻译：

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含气沉积物的混合离散气泡-格子Boltzmann-离散元模型

本文提出了一种混合的离散气泡格子Boltzmann离散元建模框架，用于模拟含气沉积物，尤其是海床中的含气沉积物。化学工程中提出的离散气泡模型适用于耦合的离散元素/晶格玻尔兹曼方法，以模拟气泡在饱和沉积物中的迁移，涉及气泡与流体/固相之间的相互作用。在这项工作中，表面张力被引入到离散气泡模型中，因此它可以处理复杂的气-液-固界面。分别采用格子玻尔兹曼法和离散元法来模拟流体流动和沉积物的力学行为。利用基于速度插值的沉浸边界方法解决了流体与固/气相之间的耦合问题。所提出的技术已通过使用流体中气泡迁移的模拟进行了初步验证，然后进行了海底沉积物中气泡传输的高分辨率研究。证明了这种混合方法可以在一定程度上再现海底沉积物试验中气泡运动的特征。