Flow State of Single Rough Fracture Based on Lattice Boltzmann Method
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摘要: 岩体中普遍存在裂隙,基于格子Boltzmann方法以及D2G9离散模型在计算流体的渗流状态下具有边界条件易于设置、计算效率较高、计算结果可视化等优点,建立考虑不同粗糙度的单一裂隙渗流模型,模型的上下边界设置为无滑移的全反弹边界,左右边界则采用非平衡外推格式的分布函数边界,同时结合经典流体力学的Poiseuille流问题,对计算模型进行验证。最后,分析岩体裂隙表面粗糙程度对渗流状态的影响,计算结果表明:随壁面粗糙程度的增加,流体的流速、大小、方向均会发生不同程度的改变,并且在由粗糙度的改变而引起隙宽急剧变化的部位,局部伴随着流体旋涡的形成,导致流体内部摩擦阻力的增大,从而产生较大的局部能量损耗。
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关键词:
- 岩体渗流 /
- 格子Boltzmann方法 /
- 单一粗糙裂隙渗流
Abstract: Based on the lattice Boltzmann method and D2G9 discrete model, a single fracture seepage model was established considering different roughness, with the advantages of the easy setting of boundary conditions, high computational efficiency, and visualization of calculation results. The upper and lower boundaries of the model were set as full rebound boundaries without slip. The distribution function boundary of the left and right edges was used in the non-equilibrium extrapolation format, and the model is verified with the Poiseuille flow problem of classical fluid mechanics. Finally, the influence of the surface roughness of rock fracture on the seepage state was analyzed. The calculation results showed that with the increase of the roughness of the wall surface, the flow velocity, size, and direction of the fluid will change to different degrees. In the parts where the gap width changes sharply due to the change of roughness, the formation of local fluid vortices will lead to the increase of internal friction resistance of the fluid, resulting in greater local energy loss.-
Key words:
- rock mass seepage /
- Lattice Boltzmann method /
- single rough fracture flow
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图 1 D2G9模型示意图[9]
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