Topic
Projectile
About: Projectile is a research topic. Over the lifetime, 13047 publications have been published within this topic receiving 115563 citations.
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TL;DR: In this paper, the use of a small number of short-duration lateral pulses acting as a control mechanism is investigated to reduce the dispersion of a direct fire rocket, and a unique control law is reported that combines model predictive control and linear projectile theory for lateral pulse jet control of an atmospheric rocket.
Abstract: Uncontrolled direct fire atmospheric rockets exhibit high impact point dispersion, even at relatively short range, and, as such, have been employed as area weapons on the battlefield To reduce the dispersion of a direct fire rocket, the use of a small number of short-duration lateral pulses acting as a control mechanism is investigated A unique control law is reported that combines model predictive control and linear projectile theory for lateral pulse jet control of an atmospheric rocket The impact point in the target plane is directly controlled Through simulation, this model predictive flight control law is shown to efficiently reduce direct fire rocket dispersion A parametric trade study on an example rocket configuration is reported that details the effect of the number and amplitude of individual pulse jets, as well as the effect of the flight control system computation cycle time
76 citations
TL;DR: In this paper, a general three-stages model, i.e., initial cratering, tunnelling and shear plugging, is developed based on dynamic cavity expansion theory and plug formation.
76 citations
TL;DR: In this paper, an inverse power-law approximation for the interaction potential between a fast-moving projectile and the atoms of an amorphous target into which it penetrates was proposed.
Abstract: By using an inverse power-law approximation for the interaction potential between a fast-moving projectile and the atoms of an amorphous target into which it penetrates, it is possible to calculate...
76 citations
TL;DR: In this article, an advanced time-accurate Navier-Stokes computational technique has been used in computational fluid dynamics to compute the unsteady aerodynamics associated with the free flight of a finned projectile at supersonic speeds.
Abstract: This article describes a new multidisciplinary computational study undertaken to compute the flight trajectories and simultaneously predict the unsteady free-flight aerodynamics of a finned projectile configuration. Actual flight trajectories are computed using an advanced coupled computational fluid dynamics/rigid body dynamics technique in a body-fixed coordinate system. An advanced time-accurate Navier–Stokes computational technique has been used in computational fluid dynamics to compute the unsteady aerodynamics associated with the free flight of the finned projectile at supersonic speeds. Computed positions and orientations of the projectile have been compared with actual data measured from free-flight tests and are found to be generally in good agreement with the data. Predicted aerodynamics forces and moments also compare well with the forces and moments used in the 6 degree of freedom fits of the results of the same tests. Unsteady numerical results obtained from the coupled method show the flowfield, the aerodynamic coefficients, and the flight paths of the projectile.
76 citations
TL;DR: In this article, a shadowgraph optical observation was performed to observe the entry process of a high-speed projectile and the formation and collapse of the cavity behind the projectile, and a number of interesting observations relating to the motion of free surface, the splash, the underwater bubbly flow and so on were found.
Abstract: When a high-speed projectile penetrates into water, a cavity is formed behind the projectile. The gas enclosed in the cavity experiences a nonequilibrium process, i.e., the gas pressure decreases as the projectile moves more deeply into water. As a result, the cavity is sealed near the free surface (surface closure) and subsequently the cavity breaks up in water (deep closure). Accompanying the break-up of the cavity, secondary shock waves appear. This is the so-called supercavitation in water entry. We describe an experimental investigation into the water entry phenomenon. Projectiles of 342 m/s were generated from a small-bore rifle that was fixed vertically in the experimental facility. The projectiles were fired into a windowed water tank. A shadowgraph optical observation was performed to observe the entry process of the projectile and the formation and collapse of the cavity behind the projectile. A number of interesting observations relating to the motion of the free surface, the splash, the underwater bubbly flow and so on were found
76 citations