In this work, a simple semi-empirical model is proposed, based on Response Surface Model, RSM, to determine the shape of an attached oblique shock wave emanating from a pointed axisymmetric nose at zero angle of attack. Extensive supersonic visualization images have been compiled from various nose shapes at different Mach numbers, along with some others performed by the author for the present p...

[1] Radiating shear and Rayleigh waves from supershear ruptures form Mach waves that transmit large-amplitude ground motion and stresses to locations far from the fault. We simulate bilateral ruptures on a finite-width vertical strike-slip fault (of width W and half-length L with L W) breaking the surface of an elastic half-space, and focus on the wavefield out to distances comparable to L. At ...

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...

We introduce continuous tools to study the low Mach number behavior of the Godunov scheme applied to the linear wave equation with porosity on cartesian meshes. More precisely, we extend the Hodge decomposition to a weighted L space in the continuous case and we study the properties of the modified equation associated to this Godunov scheme. This allows to partly explain the inaccuracy of the G...

While the propagation and refraction of waves and shocks which constitute Mach cones have been well studied in continuous slowly varying stratified media such as gases, liquids, and solids, here we investigate these processes at the kinetic, discrete (or "molecular") level in a complex plasma where the stratification scale is of the order of the damping length. The shape of Mach cones formed by...

A LL jets have noise generation due to turbulent mixing; such mixing leads to the production of Reynolds stresses, the source term within the Lighthill acoustic analogy [1]. In addition to this source, a jet that possesses coherent, large-scale structures that travel with velocities exceeding the local speed of sound will emit Mach wave radiation, a highly efficient noise production mechanism. ...

Experiments have characterized the acoustics of axisymmetric high-speed jets at a variety of Mach numbers and velocities and at pressure-matched, overexpanded, and underexpanded conditions. The effect of an annular secondary  ow on noise emission was also investigated.The fully expanded jet velocity ranged from 630 to 920m/s and the fully expanded jet Mach number ranged from 1.27 to 1.75.The s...

We consider flows past airfoils which are irrotationai and subsonic for low Mach numbers at large distances from the airfoil. If the Mach number at infinity is gradually increased, at some particular value a small supersonic region appears in the flow next to the airfoil. The flow appears to remain without shocks. If the Mach number at infinity is increased still more, a definite observable sho...

The behaviour of an initially plane, strong shock wave propagating into a conical convergence is investigated experimentally and theoretically. In the experiment a 10° half-angle cone is mounted on the end of a pressure-driven shock tube. Shock waves with initial Mach numbers varying from 6·0 to 10·2 are generated in argon at a pressure of 1·5 Torr. During each run local shock velocities at sev...

The dust explosion prevention in mines and dusted industries has been an important issue for years. During this time, many experimental and theoretical investigations have been carried out. Nevertheless, up to now nobody can declare that all the mechanisms are clear and the comprehensive mathematical model is constructed taking into account all the details of this complicated process. The gas-d...