Fast parallel algorithms for short-range molecular dynamics
Journal of Computational Physics
Domain decomposition: parallel multilevel methods for elliptic partial differential equations
Domain decomposition: parallel multilevel methods for elliptic partial differential equations
Hybrid atomistic-continuum formulations and the moving contact-line problem
Journal of Computational Physics
Statistical error in particle simulations of hydrodynamic phenomena
Journal of Computational Physics
Triple-decker: Interfacing atomistic-mesoscopic-continuum flow regimes
Journal of Computational Physics
Smoothed profile method for particulate flows: Error analysis and simulations
Journal of Computational Physics
Hybrid atomistic-continuum method for the simulation of dense fluid flows
Journal of Computational Physics
Journal of Computational Physics
Time-dependent and outflow boundary conditions for Dissipative Particle Dynamics
Journal of Computational Physics
Proper orthogonal decomposition of atomistic flow simulations
Journal of Computational Physics
Hi-index | 31.45 |
Cardiovascular pathologies, such as a brain aneurysm, are affected by the global blood circulation as well as by the local microrheology. Hence, developing computational models for such cases requires the coupling of disparate spatial and temporal scales often governed by diverse mathematical descriptions, e.g., by partial differential equations (continuum) and ordinary differential equations for discrete particles (atomistic). However, interfacing atomistic-based with continuum-based domain discretizations is a challenging problem that requires both mathematical and computational advances. We present here a hybrid methodology that enabled us to perform the first multiscale simulations of platelet depositions on the wall of a brain aneurysm. The large scale flow features in the intracranial network are accurately resolved by using the high-order spectral element Navier-Stokes solver N@e@kT@ar. The blood rheology inside the aneurysm is modeled using a coarse-grained stochastic molecular dynamics approach (the dissipative particle dynamics method) implemented in the parallel code LAMMPS. The continuum and atomistic domains overlap with interface conditions provided by effective forces computed adaptively to ensure continuity of states across the interface boundary. A two-way interaction is allowed with the time-evolving boundary of the (deposited) platelet clusters tracked by an immersed boundary method. The corresponding heterogeneous solvers (N@e@kT@ar and LAMMPS) are linked together by a computational multilevel message passing interface that facilitates modularity and high parallel efficiency. Results of multiscale simulations of clot formation inside the aneurysm in a patient-specific arterial tree are presented. We also discuss the computational challenges involved and present scalability results of our coupled solver on up to 300K computer processors. Validation of such coupled atomistic-continuum models is a main open issue that has to be addressed in future work.