Hypersonic flows of nitrogen, oxygen, argon, and carbon dioxide near a toroidal ballute have been investigated numerically using the Direct Simulation Monte-Carlo technique under transition rarefied-gas flow conditions (Knudsen numbers from 0.005 to 10). Strong influences of the geometrical factor (a ratio of the distance between the axis of symmetry and the torus disk center, and the torus rad...

A 3D simulation study for an incompressible slip flow around a spherical aerosol particle was performed. The full Navier-Stokes equations were solved and the velocity jump at the gas-particle interface was treated numerically by imposition of the slip boundary condition. Analytical solution to the Stokesian slip flow past a spherical particle was used as a benchmark for code verification, and e...

In this reply to the Comment by Li-Shi Luo, we discuss the results of the lattice Bhatnagar-Gross-Krook (LBGK) model for high-Knudsen-number (Kn) flow and heat transfer, in the range of Kn 1. We present various studies employing the LBGK model for high-Kn flow and heat transfer simulations. It is concluded that, with the use of the LBGK model in the thermal lattice Boltzmann method for Kn 0.8, ...

In this paper we propose a numerical scheme to solve the Kac model of the Boltzmann equation for multiscale rarefied gas dynamics. This scheme is uniformly stable with respect to the Knudsen number, consistent with the fluid-diffusion limit for small Knudsen numbers, and with the Kac equation in the kinetic regime. Our approach is based on the micro-macro decomposition which leads to an equival...

The spectrum of the coherent Rayleigh-Brillouin scattering (CRBS) of light by a rarefied gas is obtained by solving the Boltzmann equation numerically using the fast spectral method. The influence of the intermolecular potential on the CRBS spectrum is investigated and the accuracy of the prevailing Tenti’s s6 kinetic model is evaluated. Our numerical results show that i) the intermolecular pot...

This paper presents a simulation model for a silicon micromachined Knudsen pump that combines analytical and numerical methods. It involves numerical modeling of the thermal response, followed by an analytical estimate of the pumping using Kennard’s model. The loss of performance resulting from gas diffusion though walls of the pump is specifically addressed. The results are subsequently valida...