Direct Simulation of Shock Layer Plasmas

Journal Article · Fri May 20 00:00:00 EDT 2011 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3562655· OSTI ID:21511583

Farbar, E D; Boyd, I D ^[1]

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1. Dept. of Aerospace Engineering, University of Michigan, 1320 Beal Ave., Ann Arbor MI, 48109 (United States)

Approximate models of the electric field used with the DSMC method all impose quasi-neutrality everywhere in the shock layer plasma. The shortcomings of these models are examined in this study by simulating a weak shock layer plasma with a coupled DSMC-Particle-In-Cell (PIC) method. The stagnation streamline of an axisymmetric shock layer is simulated for entry velocities in air that correspond to both lunar and Mars return trajectories. The atmospheric densities, particle diameters and chemical reaction rates are varied from the actual values to make the computations tractable while retaining the mean free path of air at 85 km altitude. In contrast to DSMC flow field predictions, regions of non-neutrality are predicted by the DSMC-PIC method, and the electrons are predicted to be isothermal. Perhaps the most important result of this study is that the DSMC-PIC results at both reentry energies yield a 14% increase in heat flux to the vehicle surface relative to the DSMC results. Rather unintuitively, this is mostly due to an increase in ion flux to the surface, rather than the potential energy gained by each ion as it traverses the plasma sheath. In this study, an approximate electric field model is presented, with the goal of accounting for this heat flux augmentation without the need for a computationally expensive DSMC-PIC calculation of the entire flow-field. Convective heat flux results obtained with new electric field model are compared to results from the rigorous DSMC-PIC calculations.

• OSTI ID: 21511583
• Journal Information: AIP Conference Proceedings, Vol. 1333, Issue 1; Conference: 27. international symposium on rarefied gas dynamics, Pacific Grove, CA (United States), 10-15 Jul 2010; Other Information: DOI: 10.1063/1.3562655; (c) 2011 American Institute of Physics; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCOUNTING
ALTITUDE
APPROXIMATIONS
AXIAL SYMMETRY
CHEMICAL REACTIONS
DENSITY
DIFFUSION
ELECTRIC FIELDS
ELECTRONS
ENERGY YIELD
FORECASTING
HEAT FLUX
IONIZATION
LAYERS
MEAN FREE PATH
MONTE CARLO METHOD
PLASMA SHEATH
PLASMA SIMULATION
POTENTIAL ENERGY
SURFACES
VELOCITY
CALCULATION METHODS
ELEMENTARY PARTICLES
ENERGY
FERMIONS
LEPTONS
PHYSICAL PROPERTIES
SIMULATION
SYMMETRY