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Sensor Networking Software and Architectures
Published in John R. Vacca, Handbook of Sensor Networking, 2015
Muzzle blast wave of gunfire is derived from fluid dynamics processes associated to the axisymmetric muzzle blast flow of the exuding high-pressure and high-temperature plasma from the barrel. In turn, the muzzle blast flow is originated by the two-phase explosion of the cartridge propellant. The first phase corresponds to the ignition of cartridge and the following turbulent heat flow along the gun barrel, and the second comprises the re-ignition of both unburned propellant and combustion products outside the muzzle. Blast wave is the acoustic impulse of finite amplitude that diverges spherically from the weapon muzzle. In order to model acoustic impulses, Friedlander waves are used [7]. Equation 14.1 corresponds to the analytic expression of an ideal Friedlander wave with finite rise time. Here, Ps is the blast peak pressure, b represents the blast rise time, c is the impulse duration measured from overpressure to the first zero crossing, and T is the overall blast duration: pF(t)=0-∞<t<0Pst/b0≤t<bPs(1-(t-b)/c)e-(t-b)/cb≤t<∞
Interval uncertain optimization for interior ballistics based on Chebyshev surrogate model and affine arithmetic
Published in Engineering Optimization, 2021
Fengjie Xu, Guolai Yang, Liqun Wang, Quanzhao Sun
Muzzle velocity. The muzzle velocity of the projectile is an important tactical indicator reflecting the power of the artillery. The greater the muzzle velocity of the projectile, the greater the power of the artillery.Maximum chamber pressure. The maximum chamber pressure affects not only the ballistic performance of the artillery, but also the structural strength of the artillery and the projectile. Too much chamber pressure will reduce the safety of firing, but too little chamber pressure will not be conducive to the combustion of the gunpowder, the fuse arming and the acquisition of higher muzzle velocity of the projectile.Muzzle pressure. When the projectile comes out of the muzzle, the propellant gas in the muzzle still has a high pressure (49–98 MPa) and a high temperature (1200–1500 K). Propellant gas and air create complex interactions to form muzzle blast, which will reduce firing safety if the muzzle pressure is too large.Pressure wave. When the base pressure (Pd) is bigger than breech pressure (Pt), a compression wave is generated, propagating back and forth between the chamber breech and projectile base. The pressure wave not only is the main cause of abnormal interior ballistic phenomena such as bore premature and bore expansion, but also may cause an increase in muzzle velocity dispersion and a decrease in shooting accuracy. The maximum negative pressure difference on the pressure difference–time curve is usually used as an indicator of the pressure wave. A schematic diagram of the base pressure (Pd), breech pressure (Pt), muzzle pressure (Ppk) and pressure wave of the one-dimensional two-phase flow interior ballistic model is shown in Figure 5.