A general fluid-sediment mixture model and constitutive theory validated in many flow regimes
A general fluid-sediment mixture model and constitutive theory validated in many flow regimes
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DOI：
10.1017/jfm.2018.914
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发表时间：
2019-02-25
影响因子：
3.7
通讯作者：
Kamrin, Ken
中科院分区：
文献类型：
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作者：
Baumgarten, Aaron S.;Kamrin, Ken
我们提出了流体饱和沉积物的热力学一致的本构模型，从两相混合物的基本平衡定律发展而来，跨越密集到稀释的制度。该模型可以表示纯流体和干颗粒等各种极限情况。它的制定是为了捕捉一些关键的行为，例如：(i)在稳定剪切流下浸没的湿颗粒的粘性惯性流变性；（ii）颗粒的临界状态行为，它导致颗粒因剪切而发生雷诺兹膨胀/收缩；（iii）由于悬浮颗粒的存在而导致流体有效粘度的变化；（iv）在稠密和稀释混合物中观察到的达西式阻力相互作用，这导致了膨胀和流动下复杂的流体-颗粒相互作用。将全本构模型与各混合相的基本运动方程相结合，采用物质点法精确地模拟混合系统的耦合动力学。定性结果显示了该模型可以解决的问题的广度。定量结果表明，与非均匀几何中流体和颗粒行为的分析极限和实验观察相比，该模型是准确的。
We present a thermodynamically consistent constitutive model for fluid-saturated sediments, spanning dense to dilute regimes, developed from the basic balance laws for two-phase mixtures. The model can represent various limiting cases, such as pure fluid and dry grains. It is formulated to capture a number of key behaviours such as: (i) viscous inertial rheology of submerged wet grains under steady shearing flows, (ii) the critical state behaviour of grains, which causes granular Reynolds dilation/contraction due to shear, (iii) the change in the effective viscosity of the fluid due to the presence of suspended grains and (iv) the Darcy-like drag interaction observed in both dense and dilute mixtures, which gives rise to complex fluid-grain interactions under dilation and flow. The full constitutive model is combined with the basic equations of motion for each mixture phase and implemented in the material point method (MPM) to accurately model the coupled dynamics of the mixed system. Qualitative results show the breadth of problems which this model can address. Quantitative results demonstrate the accuracy of this model as compared with analytical limits and experimental observations of fluid and grain behaviours in inhomogeneous geometries.