DSMC SIMULATION OF RAREFIED RAYLEIGH FLOW

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This project focuses on the numerical simulation of Rayleigh Flow in a rarefied gas regime. Traditional Computational Fluid Dynamics (CFD), which relies on the Navier-Stokes equations and the continuum assumption, is not valid for such flows (Kn>0.1), which occur in applications like re-entry vehicles and microgravity environments.

To accurately model this behavior, the Direct Simulation Monte Carlo (DSMC) method is employed, which is a kinetic-theory approach developed by Bird (1963). DSMC works by statistically simulating the movement and collisions of a large number of representative particles, effectively solving the Boltzmann equation stochastically (from the Kinetic Theory of Gases, or KTG). This avoids the heavy computational overhead of Molecular Dynamics, which solves Newton's equations for every particle.

Key Objectives and Outcomes:

• Simulate Rayleigh Flow in the rarefied regime using the DSMC method.

• Obtain the statistically averaged velocity distribution of the flow.

• Benchmark the DSMC numerical solution against the available analytical solution for validation.

• Analyze the effect of various simulation parameters on the accuracy and efficiency of the numerical solution.

This work contributes to the understanding and accurate modeling of high-altitude or low-density gas dynamics.