We study a family of two-dimensional Riemann problems for compressible flow modeled by the nonlinear wave system. The initial constant states are separated by two jump discontinuities, x = ±κay, which develop into two interacting shock waves. We consider shock angles in a range where regular reflection is not possible. The solution is symmetric about the y-axis and on each side of the y-axis co...

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...

Mach is a new operating system targeted for distributed and multiprocessor environments. Mach contains 4.3BSD compatibility code that, unlike the Mach kernel proper, runs only on a single processor, thus presenting a performance bottleneck to a multiprocessor system. Pieces of the 4.3BSD compatibility code were selectively parallelized to reduce this bottleneck. Signifrcantly improved multiproc...

A generalized hydrodynamic theory of shock wave structures is presented for rigid diatomic gases. The theory yields shock solutions for all Mach numbers. The accuracy of the theory is examined for nitrogen gas as an example. Excellent agreement with experiment is obtained for the inverse shock widths for the entire range of Mach number studied by experiment. The comparison made shows that we ar...

An optimum airfoil design for future Mars airplane for Mars exploration is obtained by evolutionary computation coupled with a two-dimensional Reynolds-averaged Navier-Stokes solver. The optimized airfoil design is also compared with other airfoil designs optimized at different Reynolds number or at different Mach number to discuss Reynolds number and Mach number effects on airfoil design. Thes...

When a shock front in unsteady compressible flow is moving along an inclined ramp, the incident shock will be reflected by the ramp, as it moves forward. In the process of reflection, various reflected wave pattern may occur depending on the slope of the ramp and the strength of the incident shock [14, 23]. This problem is one of the most important multidimensional prototype problems in gas dyn...

A study of the mechanism by which disturbances can cause tripping between steady-flow regular and Mach reflection in the dual-solution domain is presented. Computational results indicate that the disturbance shock created as a result of the impact of dense particles on one of the shock-generating wedges can cause transition from regular to Mach reflection. The disturbance shock may also be gene...

We report the Chandra detection of a large-scale shock, on scales of 200 kpc, in the cluster surrounding the powerful radio galaxy 3C 444 (PKS 2211−17). Our 20-ks Chandra observation allows us to identify a clear surface brightness drop around the outer edge of the radio galaxy, which is likely to correspond to a spheroidal shock propagating into the intracluster medium. We measure a temperatur...