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Title: Direct Simulation of Shock Layer Plasmas

Abstract

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 ofmore » 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.« less

Authors:
;  [1]
  1. Dept. of Aerospace Engineering, University of Michigan, 1320 Beal Ave., Ann Arbor MI, 48109 (United States)
Publication Date:
OSTI Identifier:
21511583
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 1333; Journal 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; Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
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

Citation Formats

Farbar, E D, and Boyd, I D. Direct Simulation of Shock Layer Plasmas. United States: N. p., 2011. Web. doi:10.1063/1.3562655.
Farbar, E D, & Boyd, I D. Direct Simulation of Shock Layer Plasmas. United States. https://doi.org/10.1063/1.3562655
Farbar, E D, and Boyd, I D. 2011. "Direct Simulation of Shock Layer Plasmas". United States. https://doi.org/10.1063/1.3562655.
@article{osti_21511583,
title = {Direct Simulation of Shock Layer Plasmas},
author = {Farbar, E D and Boyd, I D},
abstractNote = {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.},
doi = {10.1063/1.3562655},
url = {https://www.osti.gov/biblio/21511583}, journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 1333,
place = {United States},
year = {Fri May 20 00:00:00 EDT 2011},
month = {Fri May 20 00:00:00 EDT 2011}
}