Title: Implicit Incompressible Porous Flow using SPH Show Chinese title

Title: 使用SPH的不可压缩多孔流

Abstract: We present a novel implicit porous flow solver using SPH, which maintains fluid incompressibility and is able to model a wide range of scenarios, driven by strongly coupled solid-fluid interaction forces. Many previous SPH porous flow methods reduce particle volumes as they transition across the solid-fluid interface, resulting in significant stability issues. We instead allow fluid and solid to overlap by deriving a new density estimation. This further allows us to extend modern SPH pressure solvers to take local porosity into account and results in strict enforcement of incompressibility. As a result, we can simulate porous flow using physically consistent pressure forces between fluid and solid. In contrast to previous SPH porous flow methods, which use explicit forces for internal fluid flow, we employ implicit non-pressure forces. These we solve as a linear system and strongly couple with fluid viscosity and solid elasticity. We capture the most common effects observed in porous flow, namely drag, buoyancy and capillary action due to adhesion. To achieve elastic behavior change based on local fluid saturation, such as bloating or softening, we propose an extension to the elasticity model. We demonstrate the efficacy of our model with various simulations that showcase the different aspects of porous flow behavior. To summarize, our system of strongly coupled non-pressure forces and enforced incompressibility across overlapping phases allows us to naturally model and stably simulate complex porous interactions. Show Chinese abstract

Abstract: 我们提出了一种使用SPH的新型隐式多孔流求解器，该求解器保持流体不可压缩性，并能够模拟由强耦合的固-流相互作用力驱动的广泛场景。 许多以前的SPH多孔流方法在穿过固-流界面时会减少粒子体积，导致显著的稳定性问题。 我们则通过推导新的密度估计来允许流体和固体重叠。 这进一步使我们能够将现代SPH压力求解器扩展为考虑局部孔隙率，并严格执行不可压缩性。 因此，我们可以使用流体和固体之间的物理一致压力力来模拟多孔流。 与之前使用显式力来处理内部流体流动的SPH多孔流方法不同，我们采用隐式非压力力。 我们将这些力作为线性系统求解，并与流体粘度和固体弹性进行强耦合。 我们捕捉了多孔流中最常见的效应，即由于附着力引起的阻力、浮力和毛细作用。 为了根据局部流体饱和度实现弹性行为的变化，例如膨胀或软化，我们提出了弹性模型的扩展。 我们通过各种模拟展示了我们模型的有效性，这些模拟展示了多孔流行为的不同方面。 总之，我们提出的强耦合非压力力系统以及在重叠相之间强制不可压缩性，使我们能够自然地建模并稳定地模拟复杂的多孔相互作用。