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Center for Nonlinear Studies |
There are numerous applications in science and engineering involving flows with rapid generation and evolution of (multi-material) interfacial area. The most important examples include design, optimization and safety assessment of light water reactors; atmospheric dissemination of chemical agents; explosive dispersal of liquid and solid materials; inertial confinement fusion; shock-induced powder compaction and fluidization, etc. The focus of this talk is on the numerical modeling issues for modeling these flows, i.e. how to robustly, accurately and efficiently deal with these complex multiphase, multiscale and multiphysics problems. Beside the challenge for high-fidelity interface tracking (marker-level-set algorithms), I will discuss how we address the issue of accurate spatial resolution (Structured Adaptive Mesh Refinement and recovery Discontinuous Galerkin discretization), stiff/multiple-time-scale problems (fully coupled all-speed-flow solvers using L-stable implicit Runge-Kutta), sharp-interface coupling (addressing robustness for high-acoustic-impedance gas-liquid and gas-solid contacts) and avoiding operator-splitting temporal errors using Jacobian-free Newton-Krylov framework with physics-based preconditioning. I will demonstrate that with the accurate spatio-temporal discretization and sharp-interface treatment, we are able to predict interfacial instabilities in both Rayleigh-Taylor/Richtmyer-Meshkov and viscous Kelvin-Helmholtz settings, in difference to the diffuse-interface algorithms.
Host: Mikhail Shashkov