AI 中文总结
研究多孔和裂缝材料中流体-流体驱替，开发谱计算方法研究界面演化与能量耗散，通过与模拟和实验对比验证，证明计算效率，揭示微观宏观联系及粘度对能量耗散影响，为流体流动尺度提升提供方法。
AI 中文摘要
在多孔和裂缝材料中的流体-流体驱替中，微观界面（海恩斯）跳跃中的粘性摩擦与宏观能量耗散及相关的压力-饱和度（滞留）滞后密切相关。控制模式（流速与压力）和驱动速率（从准静态到有限）会显著影响滞后现象。尽管滞后和耗散在各种技术和自然过程中很重要，但对微观和宏观尺度之间的联系以及多孔介质固有非均质性的影响仍缺乏定量理解。可变孔径的“不完美”赫勒-肖槽是一个简单的模型系统，可详细研究这些问题。然而，模拟非均质介质中的流体-流体界面演化，即使在这样简单的系统中，计算量也很大，因为需要同时解析多个长度和时间尺度。我们开发了一种用于界面演化和能量耗散的谱计算方法，并通过与计算流体动力学模拟和实验比较进行验证。通过跟踪具有单个“缺陷”以及随机粗糙度的槽中的界面演化，证明了计算效率；在这两种情况下，不同的长度尺度都会导致时间上许多数量级的非平凡动力学。我们还从理论上表明，虽然海恩斯跳跃期间的粘性力充分说明了连续亚稳平衡之间耗散的能量，但粘度不会改变总耗散量，只是改变弛豫时间。我们的方法为多孔介质中流体-流体流动的尺度提升提供了一个垫脚石。
英文摘要
In fluid-fluid displacements in porous and fractured materials, viscous friction in microscale interfacial (Haines) jumps is intimately linked to macroscale energy dissipation and the associated pressure-saturation (retention) hysteresis. The mode of control (flow rate vs. pressure) and the driving rate (from quasistatic to finite) can substantially affect hysteresis. Despite the significance of hysteresis and dissipation in various technological and natural processes, a quantitative understanding of the link between the micro- and macro-scales, and of the impact of the inherent heterogeneity of porous media, remains elusive. An ``imperfect'' Hele-Shaw cell of variable aperture is a simple model system which allows to study all these in details. However, simulating fluid-fluid interface evolution in heterogeneous media, even in such a simple system, is computationally prohibitive, as multiple length and time scales need to be resolved simultaneously. We develop here a spectral computational approach for interface evolution and energy dissipation and validate it via comparison to computational fluid dynamics simulations and experiments. Computational efficiency is demonstrated by following interface evolution in a cell with a single ``defect'', as well as with random roughness; in both, disparate length scales lead to nontrivial dynamics over many orders of magnitude in time. We also show theoretically that while viscous forces during Haines jumps fully account for the energy dissipated between consecutive metastable equilibria, viscosity does not change the total dissipated amount, merely the relaxation time. Our approach provides a stepping stone towards upscaling of fluid-fluid flows in porous media.
