Simulation and Measurements of Small Arms Blast Wave Overpressure in the Process of Designing a Silencer
Abstract Simulation and measurements of muzzle blast overpressure and its physical manifestations are studied in this paper. The use of a silencer can have a great influence on the overpressure intensity. A silencer is regarded as an acoustic transducer and a waveguide. Wave equations for an acoustic dotted source of directed effect are used for physical interpretation of overpressure as an acoustic phenomenon. Decomposition approach has proven to be suitable to describe the formation of the output wave of the wave transducer. Electroacoustic analogies are used for simulations. A measurement chain was used to compare the simulation results with the experimental ones.
Numerical and Experimental Analysis of Sound Suppressor for a 5 . 56 mm
A sound suppressor is an internal or external device coupled to the barrel of a firearm. Its development has been historically related to the negative effects produced by the noise. This article presents the numerical and experimental analysis of a sound suppressor for a 5.56 mm caliber rifle. It was designed, manufactured, and tested inside a shooting tunnel for 911 m/s and 344 m/s velocities. Three geometric configurations with curved deflectors, conical deflectors, and finally with a reactive spiral capable of dissipating the acoustic wave were compared considering reactive and dissipative systems. The attenuation of the sound inside the silencer depends directly on the reduction of the projectile wave velocity and the deflagration of the gases at the instant of firing. Then the MILSTD-1474E standard was used to carry out the experiments. The results in the computational numerical simulation show an average value of 143 dB for the considered three models, the Sound Pressure Level in the reactive core model decreased by 25% with respect to other proposals, which have an average value of 141 dB. These results can be useful to improve in the design of sound suppressors based on the needs of the users and under the specific characteristics of each weapon ballistic.
Numerical Simulation and Modeling of a Muffler
Abstract : The problem of attenuating the noise from weapons firing was studied, experimentally and numerically. As a possible method of attenuating the noise significantly, a silencer with no internal baffles was attached to the M242 cannon. The internal pressures at selected locations inside the muffler were measured. The near field overpressures outside the muffler at various polar angles were also measured. A numerical simulation of the flow through the muffler was performed, using Harten's shock capturing method to solve the Euler equations of ideal compressible flow. The numerical simulation yields a detailed picture of the flow field as displayed by the pressure and Mach contours. Pressure-time curves obtained at selected locations are compared with experimental data. There is good agreement except that the numerical simulation generates more vigorous oscillations with higher peak values. As an aid to understanding the early flow processes in the muffler and as a design tool requiring little computational effort, a one-dimensional analytical model was constructed. Gun attenuators, Impulse noise, Computation fluid dynamics, Unsteady euler, Computations.