An unstructured direct simulation Monte Carlo methodology with Kinetic-Moment inflow and outflow boundary conditions

Subsonic flow boundary conditions for the direct simulation Monte Carlo method

“…4 shows the relative difference between the predicted pressure along the center of the channel and a linear pressure distribution. The level of agreement between the simulation results and the analytical result is similar to that reported in previous work for similar configurations [3], and is generally very good. Fig.…”

“…A derivation of pressure-based subsonic inlet boundary conditions based on the local one dimensional inviscid (LODI) formulation used in continuum flow computations was recently presented in Ref. [3] for use with the DSMC method. It was also shown in this work that the previously published boundary conditions that were based on the continuum characteristic line method can be derived from the LODI formulation.…”

“…The approaches typically involve some combination of estimates of the average velocity of particles crossing the outlet boundary [9], use of the continuum characteristic line method to compute the macroscopic properties at the outlet boundary [8,10,11,13], and zeroth order extrapolation of the macroscopic properties in the first cell along the outlet to the boundary surface [12]. As was the case for the inlet boundary condition, the mathematical formulation of the characteristic line method for the pressure-based outlet boundary condition was recently rigorously derived [3].…”

“…These requirements are a result of the direction of information travel in the flow field; a more in-depth discussion of these requirements is found in Ref. [3].…”

Plume influence analysis of small bipropellant thruster on solar array of GEO satellite

“…However, some researchers have chosen to apply a Maxwellian distribution in hybrid Navier Stokes-DSMC simulations since the use of a Chapman–Enskog distribution leads to a small improvement in accuracy compared to the Maxwellian distribution [12–15] while its use would greatly increase the computational cost since more random number calls and computational operations are required [16], or because of the fact that the Chapman–Enskog distribution becomes negative with deviation from the Maxwellian distribution [12,13], or because of the observation that, for specific flows, a greater mismatch at the interface between Navier-Stokes and DSMC was observed for a Chapman–Enskog distribution as compared to a Maxwellian distribution [17]. Also, the comparison with the solution of the Burnett equation didn't reveal any problem with the usage of the Maxwellian distribution function when the Maxwellian distribution function in conjunction with kinetic-moment boundary conditions was used in the DSMC method [18]. Moreover, for a high-speed gaseous jet or plume flow from a planar or annular exit, it is considered as common and reasonable to assume that gas at the exit is in an equilibrium state [19].…”