  Multiscale non-equilibrium physics at large variations of local Knudsen
number are encountered in applications of aerospace engineering and
micro-electro-mechanical systems, such as high-speed flying vehicles and low
pressure of the encapsulation. An accurate description of flow physics in all
flow regimes within a single computation requires a genuinely multiscale
method. The adaptive unified gas-kinetic scheme (AUGKS) is developed for such
multiscale flow simulation. The AUGKS applies discretized velocity space to
accurately capture the non-equilibrium physics in the multiscale UGKS, and
adaptively employs continuous distribution functions following Chapman-Enskog
expansion to efficiently recover near-equilibrium flow region in GKS. The UGKS
and GKS are dynamically connected at the cell interface through the fluxes from
the discretized and continuous gas distribution functions, which avoids any
buffer zone between them. In this study, the AUGKS method with rotation and
vibration non-equilibrium is developed. The real gas effect in different flow
regimes has been captured. To capture aerodynamic heating accurately, the heat
flux modifications are also included. Unstructured discrete particle velocity
space is adopted to further improve the computational performance. Numerical
tests, including Sod tube, normal shock structure, high-speed flow around the
two-dimensional cylinder and three-dimensional sphere and space vehicles, and
an unsteady nozzle plume flow from the continuum flow to the background vacuum,
have been conducted to validate the current scheme. In comparison with the
original UGKS, the current scheme speeds up the computation, reduces the memory
requirement, and maintains the equivalent accuracy for multiscale flow
simulation, which provides an effective tool for non-equilibrium flow
simulations, especially for the flows at low and medium speed.
