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Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aerodynamic characteristics of muzzle noise are studied based on experimental and numerical research on jet noise induced by complex flows discharging from a large caliber small arms with a muzzle brake. The measured noise data are analyzed to distinguish the muzzle shock wave from muzzle impulse noise by the wavelet transform method. The muzzle noise is numerically simulated by a CFD-CAA hybrid method. The feasibility of the proposed method is proven by comparing the simulated results with the test results. In addition, the distribution of shock wave in muzzle brake and the directivity of muzzle noise field are analyzed based on the numerical simulation. The results indicate that the muzzle noise has a wide spectrum with high sound energy and complex components. It is found that the muzzle brake causes the lateral diversion of flow field around the muzzle, thus affecting the distribution of muzzle flow noise. [ABSTRACT FROM AUTHOR]

The lattice Boltzmann method (LBM) is studied and extended into computational aeroacoustics (CAA), and a non-equilibrium extrapolation scheme for LBM is applied to treating wall boundary and an absorbing boundary condition is used to prevent wave reflection at the far field boundary. Firstly, LBM code is validated by simulating the lid-driven cavity flow. Then, several benchmark problems in CAA are numerically studied and comparisons between LBM and conventional four-order dispersion-relation-preserving (DRP) scheme are also performed. The ability of LBM to simulate these problems is tested, which helps to further study aerodynamic noise from complex bodies. It is demonstrated that the calculated results by LBM for benchmark problems are in good agreement with the exact solution although the standard LBM has two-order accuracy in space and time, and LBM is an effective and feasible method for aero-acoustical calculations. [ABSTRACT FROM AUTHOR]