Direct simulation of gas flows at the molecular level

Bird, G. A.

doi:10.1002/cnm.1630040205

Cited by 278 publications

(470 citation statements)

References 13 publications

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“…Equations (4)(5)(6)(7)(8) provide a relationship between the surface quantities and those at the edge of the Knudsen layer (a layer which is on the order of one mean free path in thickness from the surface). The subscript w denotes conditions at the wall and s 1 refers to the edge of the Knudsen layer.…”

Section: Continuum Modelmentioning

confidence: 99%

Direct simulation Monte Carlo and Navier-Stokes simulations of blunt body wake flows

et al. 1994

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Numerical results obtained with direct simulation Monte Carlo and Navier-Stokes methods are presented for a Mach-20 nitrogen flow about a 70-deg blunted cone. The flow conditions simulated are those that can be obtained in existing low-density hypersonic wind tunnels. Three sets of flow conditions are considered with freestream Knudsen numbers ranging from 0.03 to 0.001. The focus is on the wake structure: how the wake structure changes as a function of rarefaction, what the afterbody levels of heating are, and to what limits the continuum models are realistic as rarefaction in the wake is progressively increased. Calculations are made with and without an afterbody sting. Results for the afterbody sting are emphasized in anticipation of an experimental study for the current flow conditions and model configuration. The Navier-Stokes calculations were made with and without slip boundary conditions. Comparisons of the results obtained with the two simulation methodologies are made for both flowfield structure and surface quantities. Nomenclature A = base area of cone, ird 2 /4 C D = drag coefficient, ID/p^V^A C H = heat transfer coefficient, 2q/p 00 Vl> D = drag d = base diameter Kn = Knudsen number, \/d M -Mach number M = molecular weight of N 2 , 28.02 g/mole R = gas constant for N 2 , 296.7 J/kg-K R b = cone base radius R c = corner radius Re = Reynolds number, pVd/p Re 2 = total Reynolds number, Re^ (MOO/MO) R n -nose radius S = speed ratio, V\/M/2RT s = distance along the body surface measured from the stagnation point s = temperature exponent of the coefficient of viscosity T = thermodynamic temperature 7} = internal kinetic temperature r ov = overall kinetic temperature T w = surface temperature u = axial velocity V = velocity v = radial velocity

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Section: Continuum Modelmentioning

confidence: 99%

Direct simulation Monte Carlo and Navier-Stokes simulations of blunt body wake flows

et al. 1994

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“…The Chapman-Enskog theory assumes that the velocity distribution function is a small perturbation of the equilibrium or Maxwellian function and the theory is based on the first term of an expansion in the local Knudsen numbers (e.g. Bird, 1988a). As shown in Fig.…”

Section: The Requirement For a Molecular Modelmentioning

confidence: 99%

The Direct Simulation Monte Carlo Method: Current Status and Perspectives

Bird

1990

Microscopic Simulations of Complex Flows

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“…Figure 3 shows a perspective view for the three-dimensional computational grid used in this study. The body-fitted grid has 4 x 8 x 30 cells around the body apex, 14 x 16 x 30 cells in the midsection, and 4x8x5 cells at the aft end, i.e., a total of 7840 cells. In the geometrical treatment of the body nose and side edges, six cells are placed in the circumferential direction.…”

Section: Geometry and Boundary Conditionsmentioning

confidence: 99%

Hypersonic rarefied flow about a delta wing - direct simulation and comparison with experiment

Celenligil

Moss

1992

AIAA Journal

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Three-dimensional simulations of hypersonic rarefied flow about a delta wing are performed using the direct simulation Monte Carlo method of Bird, and the results of the computations are compared with recent experimental data obtained in a vacuum wind tunnel at the DLR in Gottingen, Germany. The present study considers Mach 8.89 nitrogen flow for a range of conditions that include Knudsen numbers of 0.016-3.505 for an incidence angle of 30 deg, and angles of incidence of 15-60 deg for a constant Knudsen number of 0.389. The calculations provide details concerning the flowfield structure and surface quantities. Comparisons between the calculations and the available experimental measurements are made for aerodynamic and overall heat transfer coefficients and recovery temperature. The agreement between the measured and calculated data are very good, well within the estimated measurement uncertainty. Comparisons are also made with modified Newtonian and free-molecule theories.moment coefficient (with respect to the body apex) D = drag force d -diameter Kn = Knudsen number L = lift force / = reference length M = Mach number p = pressure q = heat transfer rate R = radius Re = Reynolds number T -temperature 7i nt = internal temperature TOY = overall temperature T r = recovery temperature T tT = translational temperature T w = wall temperature V = speed x,y,z = Cartesian coordinates a. = incidence angle of upper surface, positive leeward rj = distance along the stagnation streamline (measured from the body) p = density Presented as Paper 91-1315 at the AIAA

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Direct simulation of gas flows at the molecular level

Cited by 278 publications

References 13 publications

Direct simulation Monte Carlo and Navier-Stokes simulations of blunt body wake flows

Direct simulation Monte Carlo and Navier-Stokes simulations of blunt body wake flows

The Direct Simulation Monte Carlo Method: Current Status and Perspectives

Hypersonic rarefied flow about a delta wing - direct simulation and comparison with experiment

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