pyHiVAS: A Python-Based High-Speed Vehicle Aerodynamic Solver

Overview

pyHiVAS (Python-based High-speed Vehicle Aerodynamic Solver) is a Python-based hybrid simulation framework designed for accurate and efficient modeling of multiscale, multiphysics gas and gas–particle flows spanning continuum, rarefied, and particulate regimes.

Continuum Solver (CFD)

• The continuum module resolves high-speed compressible flows in near-continuum regimes using classical CFD techniques.
• Compressible Navier–Stokes equations

Rarefied Gas Solvers (DSMC / FP / BGK)

• For non-equilibrium regimes, pyHiVAS incorporates particle-based kinetic solvers capable of capturing molecular-level physics beyond the Navier–Stokes limit.
• Direct Simulation Monte Carlo (DSMC): Stochastic particle-based solution of the Boltzmann equation
• Fokker–Planck / BGK-type Particle Solvers: Reduced kinetic models for efficient treatment of transition regimes

Solid Particle Solvers (DEM-based)

• To model gas–particle interactions, pyHiVAS is designed to couple gas dynamics with solid particle solvers.
• Discrete Element Method (DEM) for solid particle motion

Hybrid Coupling Strategies

• pyHiVAS supports multiple hybrid coupling approaches to ensure stable and physically consistent multiscale simulations.
• Hybrid CFD–DSMC Coupling
• Hybrid FP/BGK–DSMC Coupling