A modular particle–continuum numerical method for hypersonic non-equilibrium gas flows

A modular particle–continuum (MPC) numerical method for steady-state flows is presented which solves the Navier–Stokes equations in regions of near-equilibrium and uses the direct simulation Monte Carlo (DSMC) method to simulate regions of non-equilibrium gas flow. Existing, state-of-the-art, DSMC and Navier–Stokes solvers are coupled together using a novel modular implementation which requires only a limited number of additional hybrid functions. Hybrid functions are used to adaptively position particle–continuum interfaces and update boundary conditions in each module at appropriate times. The MPC method is validated for 2D flow over a cylinder at various hypersonic Mach numbers where the global Knudsen number is 0.01. For the cases considered, the MPC method is verified to accurately reproduce DSMC flow field results as well as local particle velocity distributions up to 2.2 times faster than full DSMC simulations.