Gas-surface scattering and collisional feedback in rarefied hypersonic flow past an inclined flat plate
Abstract
Through intermolecular collisions, a gas-surface scattering law can reshape the incident molecular population on which it acts. We examine this feedback using direct simulation Monte Carlo for hypersonic flow past a 40∘ inclined flat plate at four benchmark conditions spanning 0.023≤ Kn∞≤8.439. Maxwell and Cercignani-Lampis-Lord (CLL) scattering are assessed through fixed-incidence moment references and evaluation of alternative kernels on the same recorded non-reactive incident populations. At Kn∞=0.023, Maxwell shear and heat transfer depart from diffuse-specular endpoint interpolation by up to 40% of their diffuse-reference values. In the trailing patch, the population change induced by reduced tangential CLL accommodation overturns the fixed-incidence reductions in both shear and translational heat transfer. At the two highest conditions, the CLL momentum responses become nearly componentwise, producing nearly orthogonal displacements in the drag-lift plane. Nevertheless, a total-energy constraint required by common incidence across wall laws retains a defect of 3.1% of the diffuse heat-transfer coefficient at Kn∞=8.439. Recovery of selected response relations therefore does not establish common incidence or a free-molecular flow. A cold-beam symmetry makes lift invariant under exchange of the normal and tangential CLL accommodation coefficients, but not drag. This provides a limiting explanation for the simulated asymmetric cases: at Kn∞=8.439, they yield nearly equal lift while one produces 66% more drag. Population feedback and force projection thus determine whether the conditional scattering response is reinforced, obscured or reversed in the macroscopic observables.
Related
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BibTeX
@misc{nævdal2026gassurface,
title = {{Gas-surface scattering and collisional feedback in rarefied hypersonic flow past an inclined flat plate}},
author = {Einar Nævdal and Sebastian A. Altmeyer},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.05509},
eprint = {2610.05509},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.05509},
}
RIS
TY - UNPB
TI - Gas-surface scattering and collisional feedback in rarefied hypersonic flow past an inclined flat plate
AU - Einar Nævdal
AU - Sebastian A. Altmeyer
PY - 2026
DA - 2026/10/04
PB - arXiv
DO - 10.48550/arxiv.2610.05509
UR - https://arxiv.org/abs/2610.05509
AB - Through intermolecular collisions, a gas-surface scattering law can reshape the incident molecular population on which it acts. We examine this feedback using direct simulation Monte Carlo for hypersonic flow past a 40^∘ inclined flat plate at four benchmark conditions spanning 0.023≤ Kn_∞≤8.439. Maxwell and Cercignani-Lampis-Lord (CLL) scattering are assessed through fixed-incidence moment references and evaluation of alternative kernels on the same recorded non-reactive incident populations. At Kn_∞=0.023, Maxwell shear and heat transfer depart from diffuse-specular endpoint interpolation by up to 40% of their diffuse-reference values. In the trailing patch, the population change induced by reduced tangential CLL accommodation overturns the fixed-incidence reductions in both shear and translational heat transfer. At the two highest conditions, the CLL momentum responses become nearly componentwise, producing nearly orthogonal displacements in the drag-lift plane. Nevertheless, a total-energy constraint required by common incidence across wall laws retains a defect of 3.1% of the diffuse heat-transfer coefficient at Kn_∞=8.439. Recovery of selected response relations therefore does not establish common incidence or a free-molecular flow. A cold-beam symmetry makes lift invariant under exchange of the normal and tangential CLL accommodation coefficients, but not drag. This provides a limiting explanation for the simulated asymmetric cases: at Kn_∞=8.439, they yield nearly equal lift while one produces 66% more drag. Population feedback and force projection thus determine whether the conditional scattering response is reinforced, obscured or reversed in the macroscopic observables.
ER -