A variable time step self-consistent mean field DSMC model for three-dimensional environments.

Area of Science:

• Computational Physics
• Fluid Dynamics
• Statistical Mechanics

Background:

• Direct Simulation Monte Carlo (DSMC) methods are crucial for simulating rarefied gas dynamics.
• Previous self-consistent mean field DSMC (SCMFD) algorithms were limited to one dimension.
• A need exists for more versatile and computationally efficient DSMC methods.

Purpose of the Study:

• To extend the one-dimensional SCMFD algorithm to three dimensions with a variable time step (3D-vt-SCMFD).
• To validate the 3D-vt-SCMFD method's performance across various gas collision environments.
• To assess the computational efficiency and robustness of the new algorithm.

Main Methods:

• Implementation of a 3D extension to the SCMFD algorithm.
• Introduction of a variable time step to enhance computational efficiency.
• Simulation of diverse test cases: ideal gas mixtures, Poiseuille flow, and gas expansion into vacuum.

Main Results:

• 3D-vt-SCMFD accurately reproduced properties of ideal gas mixtures, matching theoretical predictions.
• Poiseuille flow simulations showed agreement with Navier-Stokes and free molecular flow regimes.
• Gas expansion simulations yielded density, velocity, and temperature profiles consistent with analytical models.

Conclusions:

• The 3D-vt-SCMFD algorithm is a robust and computationally efficient tool for simulating a wide range of collision environments.
• The method demonstrates broad applicability, extending beyond one-dimensional systems.
• Further validation shows excellent agreement with theoretical and analytical models across different flow regimes.