Numerical study of CFD simulations for compact counter-recoil design of EOD water cannon
Explosive Ordnance Disposal (EOD) robots armed with a water cannon are deployed to disarm the improvised explosive devices. It is critical that the water cannon produces as little recoil force as possible when fired. Otherwise, the robot may be rendered immobile or damaged. In a previous work, a recoilless water cannon was designed through a specific combination of firing experiments and Computational Fluid Dynamics (CFD) simulations. The final design was conceived, prototyped and tested with real bullets. The testing results were found to be satisfactory. In this work, the CFD simulations of the final design was carried out and closely investigated. Numerical study and error analysis were performed in an attempt to find the most suitable and efficient CFD setups for this problem. Two different CFD programs, three different flow domains, and various mesh resolutions were tested.
The mechanics of the impulsive water cannon
Abstract A model is proposed to describe the operating characteristics of the impulsive water cannon. The important parameters governing the system dynamics are identified and the influence of these on performance is studied with the aid of a unique ‘ 1 1 2 D ’ finite-difference code. The algorithm upon which this code is based is described as are its principle features. The results of the calculations are compared with recently developed incompressible theory and with experiment.
Analysis of unsteady incompressible jet nozzle flow
SummaryThe mechanics of pulsed flow in a nozzle is analyzed by using the Lagrangian forms of the conservation equations for total mass and energy and the unsteady version of the Bernoulli equation. The results of the study are presented in simple formulas for predicting pressure profiles within the nozzle during the process as well as the jet velocity as a function of time. Examples are presented illustrating those parameters which are of importance and how they influence the performance of the nozzle.SommaireLa mécanique d'un écoulement transitaire à travers une buse est analysée à l'aide des formes de Lagrange des équations de conservation de la masse totale et de l'énergie et à l'aide de la version non-stationnaire de l'équation de Bernoulli. Les résultats de cette étude sont présentés sous la forme de formules simples prédisant aussi bien les profils de pression à l'intérieur de la buse que la vitesse du jet en fonction du temps. Des exemples montrent ceux des paramètres qui sont importants et de quelle manière ils influencent les performances de la buse.