The Experts below are selected from a list of 13299 Experts worldwide ranked by ideXlab platform
R. C. Swanson - One of the best experts on this subject based on the ideXlab platform.
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Progress with multigrid schemes for Hypersonic Flow problems
Journal of Computational Physics, 1995Co-Authors: Rolf Radespiel, R. C. SwansonAbstract:Several multigrid schemes are considered for the numerical computation of viscous Hypersonic Flows. For each scheme, the basic solution algorithm employs upwind spatial discretization with explicit multistage time stepping. Two-level versions of the various multigrid algorithms are applied to the two-dimensional advection equation, and Fourier analysis is used to determine their damping properties. The capabilities of the multigrid methods are assessed by solving three different Hypersonic Flow problems. Some new multigrid schemes based on semicoarsening strategies are shown to be quite effective in relieving the stiffness caused by the high-aspect-ratio cells required to resolve high Reynolds number Flows. These schemes exhibit good convergence rates for Reynolds numbers up to 200 X 10{sup 6} and Mach numbers up to 25. 32 refs., 31 figs., 1 tab.
Andrew P. Bassom - One of the best experts on this subject based on the ideXlab platform.
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Instability of Hypersonic Flow over a cone
Journal of Fluid Mechanics, 1997Co-Authors: Sharon O. Seddougui, Andrew P. BassomAbstract:The linear stability analysis of Hypersonic Flow over a sharp slender cone with an attached shock is described. Attention is focused on the viscous modes of instability which may be described by a triple-deck structure. The situation in which both the effect of the shock and the influence of curvature are important is considered in the weak-interaction region. Both neutral and non-neutral solutions are presented for both axisymmetric and non-axisymmetric disturbances. The results obtained suggest that the effect of curvature on the stability of Hypersonic Flow is significant when the attached shock is taken into account.
T.v. Poplavskaya - One of the best experts on this subject based on the ideXlab platform.
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Viscous shock layer on a cone in Hypersonic Flow
High Temperature, 2002Co-Authors: T.v. PoplavskayaAbstract:The results are given of a theoretical investigation of Hypersonic Flow past a pointed cone at zero angle of attack. The Flow characteristics are calculated using equations of complete viscous shock layer. The universal dimensionless dependence of the Stanton number on the determining parameters of the problem is obtained.
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Viscous shock layer on a plate in Hypersonic Flow
European Journal of Mechanics B-fluids, 1999Co-Authors: Anatoly A. Maslov, S.g. Mironov, T.v. Poplavskaya, A. N. Shiplyuk, V.n. VetlutskyAbstract:The results are given of a theoretical investigation of Hypersonic Flow past a pointed cone at zero angle of attack. The Flow characteristics are calculated using equations of complete viscous shock layer. The universal dimensionless dependence of the Stanton number on the determining parameters of the problem is obtained.
Rolf Radespiel - One of the best experts on this subject based on the ideXlab platform.
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Progress with multigrid schemes for Hypersonic Flow problems
Journal of Computational Physics, 1995Co-Authors: Rolf Radespiel, R. C. SwansonAbstract:Several multigrid schemes are considered for the numerical computation of viscous Hypersonic Flows. For each scheme, the basic solution algorithm employs upwind spatial discretization with explicit multistage time stepping. Two-level versions of the various multigrid algorithms are applied to the two-dimensional advection equation, and Fourier analysis is used to determine their damping properties. The capabilities of the multigrid methods are assessed by solving three different Hypersonic Flow problems. Some new multigrid schemes based on semicoarsening strategies are shown to be quite effective in relieving the stiffness caused by the high-aspect-ratio cells required to resolve high Reynolds number Flows. These schemes exhibit good convergence rates for Reynolds numbers up to 200 X 10{sup 6} and Mach numbers up to 25. 32 refs., 31 figs., 1 tab.
S T Surzhikov - One of the best experts on this subject based on the ideXlab platform.
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nonequilibrium radiative Hypersonic Flow simulation
Progress in Aerospace Sciences, 2012Co-Authors: J S Shang, S T SurzhikovAbstract:Abstract Nearly all the required scientific disciplines for computational Hypersonic Flow simulation have been developed on the framework of gas kinetic theory. However when high-temperature physical phenomena occur beneath the molecular and atomic scales, the knowledge of quantum physics and quantum chemical-physics becomes essential. Therefore the most challenging topics in computational simulation probably can be identified as the chemical–physical models for a high-temperature gaseous medium. The thermal radiation is also associated with quantum transitions of molecular and electronic states. The radiative energy exchange is characterized by the mechanisms of emission, absorption, and scattering. In developing a simulation capability for nonequilibrium radiation, an efficient numerical procedure is equally important both for solving the radiative transfer equation and for generating the required optical data via the ab-initio approach. In computational simulation, the initial values and boundary conditions are paramount for physical fidelity. Precise information at the material interface of ablating environment requires more than just a balance of the fluxes across the interface but must also consider the boundary deformation. The foundation of this theoretic development shall be built on the eigenvalue structure of the governing equations which can be described by Reynolds' transport theorem. Recent innovations for possible aerospace vehicle performance enhancement via an electromagnetic effect appear to be very attractive. The effectiveness of this mechanism is dependent strongly on the degree of ionization of the Flow medium, the consecutive interactions of fluid dynamics and electrodynamics, as well as an externally applied magnetic field. Some verified research results in this area will be highlighted. An assessment of all these most recent advancements in nonequilibrium modeling of chemical kinetics, chemical-physics kinetics, ablation, radiative exchange, computational algorithms, and the aerodynamic–electromagnetic interaction are summarized and delineated. The critical basic research areas for physic-based Hypersonic Flow simulation should become self-evident through the present discussion. Nevertheless intensive basic research efforts must be sustained in these areas for fundamental knowledge and future technology advancement.
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Interaction of a glow discharge with a rarefied Hypersonic Flow in a curvilinear channel
Russian Journal of Physical Chemistry B, 2009Co-Authors: S T SurzhikovAbstract:A two-dimensional simulation model is used to study the gasdynamic structure of a rarefied Hypersonic Flow of molecular nitrogen in a curvilinear channel in which the lower surface carries the cathode section of the discharge gap whereas the upper surface serves as the anode. The electrodynamic structure of the glow discharge (the distribution of concentrations of charged species, current density, and electric potential) is examined. It was demonstrated that the burning of a glow discharge in a rarefied Hypersonic Flow makes it possible to effectively modify the shock wave structure of the Flow.
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mechanisms of plasma actuators for Hypersonic Flow control
Progress in Aerospace Sciences, 2005Co-Authors: J S Shang, Roger L. Kimmel, Datta V. Gaitonde, James Menart, S T Surzhikov, James R HayesAbstract:Abstract A summary of recent research progress in Hypersonic plasma actuators for Flow control is attempted. It is found that the most effective plasma actuator is derived from an electromagnetic perturbation and amplifies by a subsequent viscous–inviscid interaction. Computational efforts using drift-diffusion theory and a simple phenomenological plasma model, as well as experiments in a Hypersonic plasma channel, have shown the effectiveness of using electro–aerodynamic interaction as a Hypersonic Flow control mechanism. In principle, the plasma actuator based on magneto–aerodynamic interaction should have an added mechanism in the Lorentz force, making it even more effective as a Flow control mechanism. However, this approach also incurs additional challenges and complications due to the Hall effect. Magneto–aerodynamic interactions have also been demonstrated for separated Flow control, albeit in a very limited scope. Numerical simulations based on a simple phenomenological plasma model have shown the feasibility of separated Flow suppression in shock-boundary-layer interaction over a compression ramp at a Hypersonic Flow of Mach 14.1. The control mechanism relies on the Lorentz force to energize the retarded shear layer in the viscous interacting region, but the effectiveness of momentum transfer via inelastic collision requires further validation.