Takahashi, TetsuyaLin, Ming C.Alliez, Pierre and Pellacini, Fabio2019-05-052019-05-0520191467-8659https://doi.org/10.1111/cgf.13618https://diglib.eg.org:443/handle/10.1111/cgf13618We present a grid-based fluid solver for simulating viscous materials and their interactions with solid objects. Our method formulates the implicit viscosity integration as a minimization problem with consistently estimated volume fractions to account for the sub-grid details of free surfaces and solid boundaries. To handle the interplay between fluids and solid objects with viscosity forces, we also formulate the two-way fluid-solid coupling as a unified minimization problem based on the variational principle, which naturally enforces the boundary conditions. Our formulation leads to a symmetric positive definite linear system with a sparse matrix regardless of the monolithically coupled solid objects. Additionally, we present a position-correction method using density constraints to enforce the uniform distributions of fluid particles and thus prevent the loss of fluid volumes. We demonstrate the effectiveness of our method in a wide range of viscous fluid scenarios.Computing methodologiesPhysical simulation10.1111/cgf.1361849-58