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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.

Abstract:In order to keep pace with the ongoing changes in ICT and increasing common IT competencies requirements, informatics curricula at secondary school level and, consequently, curricula educating informatics teachers must be frequently changed to ensure necessary competencies. This paper proposes collaborative development of informatics curricula assisted by a software tool for compatibility analysis of secondary school informatics curricula and curricula by which teachers of informatics are educated. The proposed software tool relies upon semantic technologies, i.e. ontologies for representation of competence-based curricula and ontology alignment for compatibility analysis. The secondary school informatics curriculum ontology was built to comply with the ACM K12 standard, while the teachers' curriculum ontology was built based on the selected existing curricula. The paper presents a brief description of the software tool and the results of the domain (informatics) segment of teachers' curriculum offered by the selected Serbian university and the standardized ACM K12 compliant secondary school informatics curriculum.

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The main subject of this paper is application of a Computational Fluid Dynamics (CFD) model in determination of the muzzle blast overpressure and its physical manifestations, as well as its validation through measurements of primary parameters. Unsteady Reynolds-averaged Navier-Stokes equations (URANS) with a corresponding turbulence model were applied for numerical simulation of complex gas-dynamic process of propellant gases release from the barrel after firing. The unstructured adaptive mesh for spatial discretization was applied, as suitable model for numerical calculation and physical interpretation of these intensive dynamic processes. The provided experimental results were compared with the results of numerical simulations, which were thus validated, according to adopted minor simplifications.