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Brinkman Penalization Method를 이용한 복잡 형상 음향 모사
한창균(C.K. Han),문영준(Y.J. Moon) 한국전산유체공학회 2017 한국전산유체공학회지 Vol.22 No.2
In this paper, we will discuss about analysis method for acoustic. A multi-block CAA(Computational Aero Acoustics) solver is implemented on the GPU(Graphics Processing Unit) to calculate massive data in reasonable times, and employing a high-order, explicit, SBP(Summation By Parts), DRP(Dispersion Relation Preserving) finite difference method due to its highly sensitive numerical characteristics to diffusion and dispersion errors. To handle complex geometry, Brinkman penalization method also has been added to the method. Noise source has been decomposed using fourier transform. First, noise sources are inserted on computational grids to verify the method. After that, counter noises were regenerated by using decomposed sources, and placed on the domain in different ways to check its to observe its behaviors(reflection, dispersion, scattering, etc.). Our final goal is to figure out appropriate counter noise parameters(number of counter sources released, places to put the counter sources, intensity of the counter sources, etc.) depending on spaces based on acoustic behavior of noise itself and SPL(Sound Pressure Level) spectrum analysis of various anti-noise source release case studies.
장인영(I.Y. Jang),한창균(C.K. Han),문영준(Y.J. Moon) 한국전산유체공학회 2017 한국전산유체공학회지 Vol.22 No.2
In this research, tonal noise characteristics of the ducted axial fan is investigated by a CFD/CAA hybrid method. A three-dimensional unsteady flow field is first calculated by the unsteady Reynolds-averaged Navier-Stokes equations. The noise sources obtained by uRANS CFD are decomposed into tonal frequencies and the corresponding acoustic fields are computed by solving the compressible Navier-Stokes equations with the six-order compact scheme and the four-stage Runge-Kutta method. With decomposed CAA solution, acoustic characteristics analysis of the ducted axial fan are conducted by identifying the spatial distribution of the noise sources at tonal frequencies.