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Our customer is the premier defence lab engaged with research & development of conventional armaments. They have been responsible for design and realization of Modern Sub Machine Carbine (MSMC), a lightweight and compact gun. The carbines are typically attached with silencer to reduce noise, couple of designs of which were required to be analysed towards final selection. Though it was possible to fabricate the prototype and evaluate the silencer performance, however, such an approach would give no information on the background physics of aero-acoustics in a gun.

Zeus Numerix employed state-of-the-art sliding mesh based CFD analysis for estimating gun noise without and with silencer. The validation of this approach, which is based on compressible ALE (Arbitrary Lagrangian-Eulerian) solver on structured multi-block mesh, was carried out first to evaluate the applicability of this novel approach. The simulation over MSMC gun involved additional complexities of handling non-abutting mesh with sliding interfaces between blocks

Left: Blast wave movement after bullet exit. Right: Peak noise levels.

Left: Blast wave movement after bullet exit. Right: Peak noise levels.

Zeus Numerix provided recommendation on the choice of silencer design based on the analysis of computational results. The customer accepted the recommendation and found correctness of simulation results from the field trials. The study came very helpful in building confidence levels among users that design of the silencer followed a thorough analysis and evaluation.