TY - GEN
T1 - Computation of hypersonic flow of a diatomic gas in rotational nonequilibrium past 3D blunt bodies using the Generalized Boltzmann Equation
AU - Wilson, Christopher D.
AU - Agarwal, R. K.
AU - Cheremissine, F. G.T.
N1 - Funding Information:
Funding provided by the Intramural Program of the National Human Genome Research Institute, National Institutes of Health (LE). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We thank Kristin Harper for editorial assistance.
PY - 2009
Y1 - 2009
N2 - The results of 3-D numerical simulations of hypersonic flow of a diatomic gas, namely the nitrogen past 3-D blunt bodies (an axisymmetric blunt body, bicone and a hollow-cylinder-flare) at low to high Knudsen numbers Kn are presented. In a previous paper, AIAA 2007-0205, flow field simulations in a monoatomic gas were reported by employing several computational models namely the Navier-Stokes equations, Burnett equations, Direct Simulation Monte Carlo (DSMC), and the classical Boltzmann equation. The effect of Knudsen number Kn varying from 0.01 to 10 was investigated for Mach 3 flow past a 2D blunt body. In a follow-up paper, AIAA 2007-4550, computations for flow of nitrogen in rotational non-equilibrium past a 2D blunt body were reported by solving the Generalized Boltzmann Equation (GBE) [1]. In this paper, the hypersonic flow fields past complex axisymmetric blunt bodies at angle of attack in a diatomic gas are computed using the 3D GBE code for Kn varying from 0.1 to 10. In the GBE (same as the Wang-Chang Uhlenbeck Equation (WC-UE) except that it includes the degenerate rotational energy states explicitly), the internal and translational degrees of freedom are considered in the framework of quantum and classical mechanics respectively. The computational framework available for the standard Boltzmann equation (for a monoatomic gas with translational degrees of freedom) [3] is extended by including the rotational degrees of freedom in the GBE. The general computational methodology for the solution of the GBE for a diatomic gas is similar to that for the standard BE except that the evaluation of the collision integral becomes significantly more complex due to the quantization of rotational energy levels. The solution of GBE requires modeling of transition probabilities, elastic and inelastic cross-sections etc. of a diatomic gas molecule, needed for the solution of the collision integral. An efficient computational methodology has been developed for the solution of GBE for computing the flow field in diatomic gases at high Mach numbers.
AB - The results of 3-D numerical simulations of hypersonic flow of a diatomic gas, namely the nitrogen past 3-D blunt bodies (an axisymmetric blunt body, bicone and a hollow-cylinder-flare) at low to high Knudsen numbers Kn are presented. In a previous paper, AIAA 2007-0205, flow field simulations in a monoatomic gas were reported by employing several computational models namely the Navier-Stokes equations, Burnett equations, Direct Simulation Monte Carlo (DSMC), and the classical Boltzmann equation. The effect of Knudsen number Kn varying from 0.01 to 10 was investigated for Mach 3 flow past a 2D blunt body. In a follow-up paper, AIAA 2007-4550, computations for flow of nitrogen in rotational non-equilibrium past a 2D blunt body were reported by solving the Generalized Boltzmann Equation (GBE) [1]. In this paper, the hypersonic flow fields past complex axisymmetric blunt bodies at angle of attack in a diatomic gas are computed using the 3D GBE code for Kn varying from 0.1 to 10. In the GBE (same as the Wang-Chang Uhlenbeck Equation (WC-UE) except that it includes the degenerate rotational energy states explicitly), the internal and translational degrees of freedom are considered in the framework of quantum and classical mechanics respectively. The computational framework available for the standard Boltzmann equation (for a monoatomic gas with translational degrees of freedom) [3] is extended by including the rotational degrees of freedom in the GBE. The general computational methodology for the solution of the GBE for a diatomic gas is similar to that for the standard BE except that the evaluation of the collision integral becomes significantly more complex due to the quantization of rotational energy levels. The solution of GBE requires modeling of transition probabilities, elastic and inelastic cross-sections etc. of a diatomic gas molecule, needed for the solution of the collision integral. An efficient computational methodology has been developed for the solution of GBE for computing the flow field in diatomic gases at high Mach numbers.
UR - https://www.scopus.com/pages/publications/77958489826
M3 - Conference contribution
AN - SCOPUS:77958489826
SN - 9781563479755
T3 - 41st AIAA Thermophysics Conference
BT - 41st AIAA Thermophysics Conference
T2 - 41st AIAA Thermophysics Conference
Y2 - 22 June 2009 through 25 June 2009
ER -