Direct Simulation Monte Carlo Simulations of Hypersonic Flows With Shock Interactions

Moss, James N.; Bird, G. A.

doi:10.2514/1.12532

Cited by 81 publications

(44 citation statements)

References 6 publications

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“…4 shows a comparison of both simulation variants with pressure measurements for the 50 km-condition. In accordance with the observation of Moss and Bird [3], the choice of α v has no impact on pressure-both simulations agree well with the measurements. When comparing the simulations to measurements of heat flux at the same condition, however, differences show up, as shown in Fig.…”

Section: Discussionsupporting

confidence: 77%

“…The extra energy stored in the vibrational mode results in a flow condition different to an atmospheric flight test, and could lead to increased surface heat flux in case the molecules transfer vibrational energy during surface collisions. The issue has been addressed several times, however with vastly different assumptions and conclusions for the vibrational energy accommodation at the wall, ranging form nearly full accommodation [3] to hardly any, i.e. a vibrationally inert or non-catalytic surface [4].…”

mentioning

confidence: 99%

“…Their comparison of Navier-Stokes-based CFD simulations with heat flux measurements on a biconcic model was in best agreement when assuming vibrationally adiabatic surface (α v = 0), although slip boundary conditions had to be used as a consequence of the low density flow condition. To also asses the influence of α v on surface heat flux induced by a hypersonic shock tunnel flow around a double-cone, Moss and Bird [3] compared DSMC (direct simulation Monte Carlo) simulations with both full vibrational surface accommodation (α v = 1) as well as no accommodation at all (α v = 0), respectively, to heat transfer measurements taken at a low-density Mach 15.6 condition. They found that (α v = 1) leads to about 12% higher local heating rates compared to (α v = 0), however the differences to the measurements were of a similar magnitude.…”

mentioning

confidence: 99%

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Influence of Molecular Vibrational Energy Accommodation Modeling on Cone Surface Heat FLUX at Mach 10

Hruschka¹,

Sauerwein²

2016

JEPE

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Abstract:In order to assess the influence of high vibrational temperatures typically found in shock-tunnel-generated flows on model surface heat flux, measurements are compared to simulations using the DSMC (direct simulation Monte Carlo) method. The two limiting cases of either full accommodation of molecular vibrational energy to the surface temperature or none at all are simulated for three shock tunnel conditions using Nitrogen (N 2 ) as a test gas. The conditions mainly differ by an order of magnitude in density, however, all three comparisons to the corresponding measurements suggest that vibrational surface relaxation happens only to a small extent. While model surface pressure is not affected, heat fluxes differ by up to 20%, depending on the modelling. Furthermore, lower flow densities generally lead to higher differences.

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Section: Discussionsupporting

confidence: 77%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Influence of Molecular Vibrational Energy Accommodation Modeling on Cone Surface Heat FLUX at Mach 10

Hruschka¹,

Sauerwein²

2016

JEPE

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“…Although profiles of shear stress are not shown here (and were not measured experimentally), the point of separation x sep predicted by MONACO for each sampling interval is listed in Table 1. By noting the percentage change in x sep per millisecond, it is evident that the size of the separation region has effectively reached steady state after 1.5 ms. DSMC simulations of the same case performed by Moss and Bird [29] draw the same conclusion and predict a level of agreement with experimental data similar to the MONACO results in Fig. 2b.…”

Section: Full Navier-stokes and Dsmc Simulationsupporting

confidence: 76%

“…For this reason, fine resolution (cell size and time step) is required for the flare region in a DSMC simulation. Subsequent DSMC simulations [29] have improved the resolution and produced excellent results, compared with the experimental data. The MONACO code, as already described, is used to calculate the flowfield and surface properties for the preceding run-11 flow conditions using both mesh 2 and mesh 3.…”

Section: Full Navier-stokes and Dsmc Simulationmentioning

confidence: 99%

Hybrid Particle-Continuum Simulations of Hypersonic Flow Over a Hollow-Cylinder-Flare Geometry

2008

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A modular particle-continuum numerical method is used to simulate steady-state hypersonic flow over a hollowcylinder-flare geometry. The resulting flowfield involves a mixture of rarefied nonequilibrium flow and high-density continuum flow. The hybrid particle-continuum method loosely couples direct simulation Monte Carlo and NavierStokes methods, which operate in different regions, use different mesh densities, and are updated using differentsized time steps. Hybrid numerical results are compared with full particle and full continuum simulations as well as with experimental data. The hybrid particle-continuum simulations are demonstrated to reproduce experimental and full particle simulation results for surface and flowfield properties including velocity slip, temperature jump, thermal nonequilibrium, heating rates, and pressure distributions with high accuracy. The hybrid method, which uses particle simulation next to the surface, is also shown to predict accurate heating rates even when a highly dissipative numerical scheme is used for the continuum solver. For this particular flow, a hybrid simulation is obtained with modest computational savings over full particle simulation. NomenclatureBr cutoff = cutoff value of the continuum-breakdown parameter

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Non‐Continuum Phenomena in Hypersonic Flow

Boyd

2010

Encyclopedia of Aerospace Engineering

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At high altitude in the trajectory of a hypersonic entry vehicle, the atmospheric density is low, leading to relatively infrequent intermolecular collisions. The low collision rate produces physical flow phenomena which cannot be predicted accurately using a continuum description. This chapter describes the most important of these non‐continuum phenomena for hypersonic flow analysis and the conditions under which they occur. A numerical technique for analysis of non‐continuum flows is described and its success demonstrated through comparison with measurements collected in laboratory and flight experiments, and with results generated using the continuum approach.

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Direct Simulation Monte Carlo Simulations of Hypersonic Flows With Shock Interactions

Cited by 81 publications

References 6 publications

Influence of Molecular Vibrational Energy Accommodation Modeling on Cone Surface Heat FLUX at Mach 10

Influence of Molecular Vibrational Energy Accommodation Modeling on Cone Surface Heat FLUX at Mach 10

Hybrid Particle-Continuum Simulations of Hypersonic Flow Over a Hollow-Cylinder-Flare Geometry

Non‐Continuum Phenomena in Hypersonic Flow

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