Two recent numerical studies of hypersonic flows over bodies with concavities revealed problems with convergence to a steady state with an oft-used application of local-time-stepping. Both simulated flows showed a time-like, periodic shedding of vortices in a subsonic domain bounded by supersonic external flow although the simulations, using local-time-stepping, were not time accurate. Simple m...

In the present work, we propose a reformulation of the fluxes and interpolation calculations in the PISO method, a well-known pressure-correction solver. This new reformulation introduces the AUSM up flux definition as a replacement for the standard Rhie and Chow method of obtaining fluxes and central interpolation of pressure at the control volume faces. This algorithm tries to compatibilize t...

In this paper, we prove the existence and stability of subsonic flows for steady full Euler-Poisson system in a two dimensional nozzle of finite length when imposing the electric potential difference on non-insulated boundary from a fixed point at the entrance, and prescribing the pressure at the exit of the nozzle. The Euler-Poisson system for subsonic flow is a hyperbolic-elliptic coupled non...

We prove that the sonic surface of axi-symmetric meridional stationary flows is always attached to the accretor, however small, if the adiabatic index of the gas is γ = 5/3. Using local expansions near a point-like accretor, we extend Bondi's classification of spherically symmetric flows to axisymmetric flows, introducing the possibility of angular sectors reached by no flow lines, and singular...

The effects of toroidal and poloidal flows on the equilibrium of tokamak plasmas are numerically investigated using the code FLOW. The code is used to determine the changes in the profiles induced by large toroidal flows on NSTX-like equilibria @with NSTX being the National Spherical Torus Experiment, M. Ono, S.M. Kaye, Y.-K.M. Peng et al., Nucl. Fusion 40, 557 ~2000!# where flows exceeding the...

A nanosecond pulsed plasma discharge located between two fuel jets is used to ignite and hold jet flames in supersonic crossflows, without the use of additional devices (e.g., cavities or backsteps) for flame holding. The fuel injection nozzles and discharge electrodes are mounted flush with the surface of the flat wall adjacent to the freestream flow. The nonequilibrium plasma is produced by r...

We develop numerical boundary conditions for the compressible Navier–Stokes equations based on a generalized relaxation approach (GRCBC), which hinges on locally one-dimensional characteristic projection at the computational boundaries, supplemented with available information from the flow exterior. The basic idea is to estimate the amplitude of incoming characteristic waves through first-order...

A constraint exists for intrusive probes in transonic flow which leads to a complete insensitivity to static pressure at Mach number Ma=1. Nearby Mach number unity different types of probes are affected more or less by the reduced sensitivity to static pressure or Mach number. In this paper three types of probes are compared and it is shown that the reduced sensitivity near Ma=1 causes large er...

We prove that the sonic surface of axisymmetric meridional stationary flows is always attached to the accretor, however small, if the adiabatic index of the gas is = 5=3. Using local expansions near a point-like accretor, we extend Bondi’s classification of spherically symmetric flows to axisymmetric flows, introducing the possibility of angular sectors reached by no flow lines, and singular di...

The heliosphere is the bubble the Sun carves out of the interstellar medium. The solar wind moves outward at supersonic speeds and carries with it the Sun’s magnetic field. The interstellar medium is also moving at supersonic speeds and carries with it the interstellar magnetic field. The boundary between the solar wind and the interstellar medium is called the heliopause. Before these plasmas ...