Subsonic Jets

Application of this procedure to inadvertently ignited safety valve discharges can involve a special problem. Certain combinations of pressure ratio and length of safety valve riser can result in choked flow, with a pressure discontinuity at the exit. The pressure of the jet then adjusts to atmospheric pressure in a system of shock waves or expansion waves over a distance of a few pipe diameters. These waves can affect the local mixing of the jet with the crosswind. Since the calculation procedure incorporates correlations for subsonic jets, it cannot be expected to be entirely accurate in this case. Nevertheless, since the wave system... 

Changes in total ozone column concentrations can also arise from changes in other trace species, including N2O, CH4, NOx and CO2. The growth in the use of subsonic jet aircraft during the past 25 years has... 

The momentum transfer factor f. depends on the adiabatic exponent of the gas and differs for supersonic and subsonic jets. The turbulence field is described by turbulence intensity u / ax and the turbulence length scales L and 1. 

Fig. 1. The schematic of the jet interaction process a) Subsonic jets, b) Supersonic jets.

Witze Am. In.st. Aeronaut. Astronaut. J., 12, 417-418 [1974]) gives equations for the centerline velocity decay of different types of subsonic and supersonic circular free jets. Entrainment of surrounding fluid in the region of flow establishment is lower than in the region of estabhshed flow (see Hill, J. Fluid Mech., 51, 773-779 [1972]). Data of Donald and Singer (T/V7/1.S. In.st. Chem. Eng. [London], 37, 255-267... 

When a jet fire has decayed to a pressure of 10 psig the fire is assumed to have effectively ceased. This pressure is close to the transition pressure from sonic to subsonic flow. When a jet fire event has decayed to this level, its magnitude and exposure potential are considered to have reached a threshold level below which no significant further damage can occur (i.e., no escalation potential) and active fire fighting measures can effectively bring the fire under control. 

Figure 13.1 Near-field entrainment measurements in noncircular jets based on experimental and computational studies [16]. Subsonic regimes. Experiments 1 — elliptic [37] 2 — square [16] 3 — round [38]. Simulations 4 — square [16]. A ...

Grinstein, F. F., E. Gutmark, and T. P. Parr. 1995. Near-held dynamics of subsonic, free square jets. A computational and experimental study. J. Physics Fluids 1 1483-97. 

Schulte, P., H. Schlager, H. Ziereis, U. Schumann, S. L. Baughcum, and F. Deidewig, NO, Emission Indices of Subsonic Long-Range Jet Aircraft at Cruise Altitude In Situ Measurements and Predictions, . /. Geophys. Res., 102, 21431-21442 (1997). 

The basis for concern is that the HSCTs are designed to fly at much higher altitudes than the existing commercial jets and hence increase direct emissions into the stratosphere. The HSCT was proposed to carry about 250-300 passengers and to fly from Los Angeles to Tokyo, for example, in about 4 h, compared to more than 10 h for subsonic aircraft. These aircraft emit NOx, CO, C02, H20, S02, and soot. Our understanding of the chemistiy of the stratosphere is now much more detailed. The effects of emissions of NOx as well... 

Classification, Missiles are commonly classified by their launch and target environments, as well as by popular names. Other methods of classifying guided missiles are by trajectory, speed (subsonic, sonic or supersonic), propulsion (air breathers, usually jets or rockets), guidance (command, Inertial or homing), payload (such as nuclear, high explosive, or electronic jammer), and purpose (strategic or tactical, offensive or defensive)... 

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]. 

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