Dynamic pressure, impact

Diamonds also occur in meteorites, probably as a result of high pressures produced dynamically by impact (10,11). The shock or explosive mode of synthesis is a viable process for fine diamond powders of both the cubic and hexagonal (lonsdaleite) polymorphs (12) naturally or otherwise. Some diamonds in space appear to have formed by processes more closely related to the low pressure chemical vapor deposition processes described later (see... 

Dynamic pressure may be measured by use of a pitot tube that is a simple impact tube. These tubes measure the pressure at a point where the velocity of the fluid is brought to zero. Pitot tubes must be parallel to the flow. The pitot tube is sensitive to yaw or angle attack. In general angles of attack over 10° should be avoided. In cases where the flow direction is unknown, it is recommended to use a Kiel probe. Figure 10-3 shows a Kiel probe. This probe will read accurately to an angle of about 22° with the flow. 

Chile [Prog. Aerosp. Sc7, 16, 147-223 (1975)] reviews the use of the pitot tube and allied pressure probes for impact pressure, static pressure, dynamic pressure, flow direction and local velocity, sldn friction, and flow measurements. 

In most flat-plate impact experiments, the direction of motion of the impacting plate is normal to its surface, such that only a planar compressive shock is introduced into the specimen. Within the last fifteen years, however, techniques have been developed for dynamic pressure-shear loading of specimens (Abou-Sayed et al., 1976 Chhabildas and Swegle, 1980). These involve an oblique impact, as illustrated in Fig. 3.6, in which the impact surface on the... 

Scanning electron microscopic examination of pure, dextrinated and RD 1333 LA) 10) L. Avrami N. Palmer, Impact Sensitivity of Lead Azide in Various Liquids with Different Degrees of Confinement , PATR 3965 (1969) 11) M.F. Zimmer L.D. Lyston, Dynamic Pressure Measurements on Small Amounts of Detonating Lead Azide , Explosivst 18, No 1, 12-15 (Jan 1970) 12) R.W. Hutchinson,... 

Autoffettage is a useful measure for statically as well as dynamically pressurized vessels (see section 4.1.5.1). There is also a benifitial impact on the decrease of the rate of crack growth and the increase of the critical crack depth. 

Impact (dynamic) pressure (for the determination of amount and, respectively, velocity of gas)... 

Estimation of the pressure drop over a cascade impactor is important for both design and operations of the device. A simple method for the estimation is to assume that the dynamic pressure head of the jet is lost due to turbulence. Hence, the pressure drop in an impaction stage is estimated by (Reist, 1993)... 

Other conditions, the advancing length is to two or three times more, so mining time will be longer, it can reduce the impact of mining dynamic pressure to mining in nearby coal face. 

Fig. 10.4 Generation of high dynamic pressures by projectile impact a light gas gun, b square-bore rail gun, side view, c the same, viewed down the barrel. (Adapted from Fig. 1 in [336] (Copyright 2004 Kluwer Academic Publishers) with kind permission from Springer Science and Business Media B.V.)...

Avoid "dynamic pressure" readings. Figure 52.3 illustrates the problem. The kinetic energy of the high-velocity inlet fluid will be converted to pressure as it impacts the vessel wall at Pi. This is called a dynamic pressure. The pressure at F2 will be lower than Pi. The correct pressure to read is the static pressure measured at P2. 

Missiles may be generated when combustion (deflagration or detonation) occurs in a confined region or when a propagating combustion front produces dynamic pressure loads on equipment. Such missiles may pose a threat to the containment structure itself, as well as representing a potential threat to safety and control equipment. For instance, electrical cables may not be expected to withstand the impact of a door or metal box. The actual risk to plant safety posed by missiles generated from hydrogen combustion depends upon a number of independent factors and is very difficult to predict. 

G.T. Gray III and P.S. Follansbee, Influence of Peak Pressure and Pulse Duration on the Substructure Development and Threshold Stress Measurements in Shock-loaded Copper, in Impact Loading and Dynamic Behavior of Materials (edited by C.Y. Chiem, H.-D. Kunze, and L.W. Meyer), Deutsche Gesellschaft fuer Metall-kunde, Germany, 1988, 541 pp. 

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