@article{Xue:2020:NFD, author = {Xue, Tao and Su, Haozhe and Han, Chengguizi and Jiang, Chenfanfu and Aanjaneya, Mridul}, title = {A Novel Discretization and Numerical Solver for Non-Fourier Diffusion}, year = {2020}, issue_date = {December 2020}, publisher = {Association for Computing Machinery}, address = {New York, NY, USA}, volume = {39}, number = {6}, issn = {0730-0301}, url = {https://doi.org/10.1145/3414685.3417863}, doi = {10.1145/3414685.3417863}, abstract = {We introduce the C-F diffusion model [Anderson and Tamma 2006; Xue et al. 2018] to computer graphics for diffusion-driven problems that has several attractive properties: (a) it fundamentally explains diffusion from the perspective of the non-equilibrium statistical mechanical Boltzmann Transport Equation, (b) it allows for a finite propagation speed for diffusion, in contrast to the widely employed Fick's/Fourier's law, and (c) it can capture some of the most characteristic visual aspects of diffusion-driven physics, such as hydrogel swelling, limited diffusive domain for smoke flow, snowflake and dendrite formation, that span from Fourier-type to non-Fourier-type diffusive phenomena. We propose a unified convection-diffusion formulation using this model that treats both the diffusive quantity and its associated flux as the primary unknowns, and that recovers the traditional Fourier-type diffusion as a limiting case. We design a novel semi-implicit discretization for this formulation on staggered MAC grids and a geometric Multigrid-preconditioned Conjugate Gradients solver for efficient numerical solution. To highlight the efficacy of our method, we demonstrate end-to-end examples of elastic porous media simulated with the Material Point Method (MPM), and diffusion-driven Eulerian incompressible fluids.}, journal = {ACM Trans. Graph.}, month = nov, articleno = {178}, numpages = {14}, keywords = {fick's law, C-F diffusion, MPM, convection-diffusion, multigrid solver, non-fourier, incompressble flow} }