1 research outputs found
Efficient parallel solver for high-speed rarefied gas flow using GSIS
Recently, the general synthetic iterative scheme (GSIS) has been proposed to
find the steady-state solution of the Boltzmann equation in the whole range of
gas rarefaction, where its fast-converging and asymptotic-preserving properties
lead to the significant reduction of iteration numbers and spatial cells in the
near-continuum flow regime. However, the efficiency and accuracy of GSIS has
only been demonstrated in two-dimensional problems with small numbers of
spatial cell and discrete velocities. Here, a large-scale parallel computing
strategy is designed to extend the GSIS to three-dimensional high-speed flow
problems. Since the GSIS involves the calculation of the mesoscopic kinetic
equation which is defined in six-dimensional phase-space, and the macroscopic
high-temperature Navier-Stokes-Fourier equations in three-dimensional physical
space, the proper partition of the spatial and velocity spaces, and the
allocation of CPU cores to the mesoscopic and macroscopic solvers, are the keys
to improving the overall computational efficiency. These factors are
systematically tested to achieve optimal performance, up to 100 billion spatial
and velocity grids. For hypersonic flows around the Apollo reentry capsule, the
X38-like vehicle, and the space station, our parallel solver can get the
converged solution within one hour