Flow regime supersonic

According to the equations for supersonic pipe flow, pressure increases and velocity decreases in the direction of flow. However, this flow regime is unstable, and a supersonic stream entering a pipe of constant cross section undergoes a compression shock, the result of which is an abrupt and finite increase in pressure and decrease in velocity to a subsonic value. 

The schematic of gas-particle jet interaction zone is shown in Fig. 1. The configuration of this zone (milling zone) differs in dependence on a jet flow regime (subsonic a) or supersonic b)). The diameter of an accelerating nozzle equals Dj. Parameters of a mixture at... 

Moreover the comparison of 3S and TET installations under transonic and supersonic regimes clearly shows 3S advantages, providing that gas flow is not essentially lean. 

Rowe and co-workers are developing a so-called diffusion technique to extend the temperature and pressure range. The technique will use the conversion of the initial kinetic energy (per unit volume) of the jet into a pressure increase downstream of the mass spectrometer, when the flow is brought from a supersonic to a subsonic regime through suitably shaped tubing. Also, it has been shown that the use of pulsed Laval nozzles reduces the appreciable amounts of gas that are consumed in the continuous flow CRESU apparatus [55]. 

Several wind models of analytical nature exist. They differ in their level of physical sophistication and in their way to parametrize the wind characteristics. In all cases, the wind is assumed to be spherically symmetric, which appears to be a reasonable first approximation even in two-dimensional simulations, at least late enough after core bounce. In addition, the wind is generally treated as a stationary flow, meaning no explicit time dependence of any physical quantity at a given radial position. Newtonian and post-Newtonian descriptions of a spherically symmetric stationary neutrino-driven (supersonic) wind or (subsonic) breeze emerging from the surface of a PNS have been developed. The reader is referred to [24] for the presentation of a Newtonian, adiabatic and steady-state model for the wind and breeze regimes, and for a general-relativistic steady-state wind solution. 

It is shown in specialized texts on fluid dynamics that a convergent-diveigent nozzle is needed to accelerate a gas from subsonic to supersonic conditions, since gas acceleration in the subsonic regime requires the flow area to diminish with speed, while gas acceleration from sonic to supersonic speeds requires the flow area to expand with speed. The subsonic, convergent part of the nozzle is linked to the supersonic, divergent part of the nozzle by a duct of constant flow area, known as the throat, which is kept very short in practice in order to avoid frictional losses. The throat is the only section of the nozzle in which sonic flow can occur, and it is impossible for the throat to support any speed greater than sonic. The above remarks apply to all polytropic... 

Beam Spectroscopy. Both specificity and sensitivity can be gready enhanced by suppressing collisional and Doppler broadening. This is accomplished in supersonic atomic and molecular beams (296) by probing the beam transversely to its direction of flow in a near-collisionless regime. 

Usually, the regime of gas flow in a macrochannel refers to viscous and compressibility effects, respectively quantified by the Reynolds number Re and the Mach number Ma. For low Reynolds numbers (typically for Re < 2,000), the flow is laminar and it becomes turbulent for higher values of Re. For Ma < 1, the flow is subsonic and for Ma > 1, it is supersonic. Generally, if Ma > 0.3, compressibility effects should be taken into account. 

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