Reliable ignition in high-speed flows represents a significant scientific problem with a wide range of practical applications. Scientifically, the ignition processes involve complicated interactions among various aspects of chemical reaction and turbulence, which are not fully understood yet [1]. Reliable ignition in propulsion and power devices is further complicated by practical factors such ...

We present two-dimensional hydrodynamical simulations of corotating stream structure in the wind from a rotating O star, together with resulting synthetic line profiles showing discrete absorption components (DACs). An azimuthal variation is induced by a local increase or decrease in the radiative driving force, as would arise from a bright or dark “star spot” in the equatorial plane. Since muc...

We give an example of supersonic solutions to a one-dimensional steady state Euler-Poisson system arising in the modeling of plasmas and semiconductors. The existence of the supersonic solutions which correspond to large current density is proved by Schauder’s fixed point theorem. We show also the uniqueness of solutions in the supersonic region.

Aero-optical environment of the supersonic flow in Trisonic Gasdynamic Facility (TGF) wind tunnel at Wright-Patterson AFB was experimentally measured using a high-speed wavefront sensor. Temporallyand spatially-resolved wavefronts were collected at a range of Mach numbers between 1.5 and 3.0 and the range of Reynolds numbers between 1 and 4 million per foot. Several data reduction techniques, i...

We report on the deep (100 ksec) XMM-Newton/EPIC observation of the field of the Geminga pulsar. The unprecedented throughput of the instrument allowed to detect two elongated parallel x-ray tails trailing the neutron star. They are aligned with the object's supersonic motion, extend for ∼2', and have a nonthermal spectrum produced by electron-synchrotron emission in the bow shock between the p...

The theory of moving reversing layers for hot stars is updated to include an extensive line list, a radiative boundary condition from static model atmospheres, line transfer by scattering, and continuation to supersonic velocities. A Monte Carlo technique determines the theory's eigenvalue J, the mass flux, and the derived J's are in good agreement with the wind models of Pauldrach et al. (2001...

-Hh1s paper reports recent progress 1n vortex-control applications for alleviating the adverse consequences of three-dimensional separation and vortical Interactions on slender body/swept wing configurations. Examples Include: helical separation trip to alleviate the side force due to forebody vortex asymmetry; hinged strakes to avoid vortex breakdown effects; compartmentatlon ... swept leading...

Many astrophysical flows occur in inhomogeneous media. The broad-line regions (BLR) of active galactic nuclei (AGNs) are one of the important examples where emission-line clouds interact with the outflow. We present results of a numerical study of the interaction of a steady, planar shock / supersonic postshock flow with a system of embedded cylindrical clouds in a two-dimensional geometry. Det...

-Hh1s paper reports recent progress 1n vortex-control applications for alleviating the adverse consequences of three-dimensional separation and vortical Interactions on slender body/swept wing configurations. Examples Include: helical separation trip to alleviate the side force due to forebody vortex asymmetry; hinged strakes to avoid vortex breakdown effects; compartmentatlon ... swept leading...

We used magnetohydrodynamic (MHD) simulations of interstellar turbulence to study the probability distribution functions (PDFs) of increments of density, velocity, and magnetic field. We found that the PDFs are well described by a Tsallis distribution, following the same general trends found in solar wind and Electron MHD studies. We found that the PDFs of density are different in subsonic and ...