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효율적인 음향 윈도우 설계를 위한 2차원 유한요소법 기반의 과도 해석
김유창(Kim, Y.C.),김석구(Kim, S.K.),윤석왕(Yoon, S.W.),이영관(Lee, Y.),조미숙(Cho, M.S.),신구균(Shin, Ku-Kyun),구자춘(Koo, J.C.) 한국소음진동공학회 2009 한국소음진동공학회 논문집 Vol.19 No.7
The efficiency of active sonar that is used underwater observation equipment is important for obtain the information of topography and trace for the objects. Sound wave transmitted from sonar are distorted by acoustic window which is to protect sonar. Making various sonar dome is impossible for experiment, because consumed unnecessary time and expense. So, the purpose of this study is to simulate and analyze the acoustic window propagated sound wave from sonar for designing model reduced insertion loss. Simulation is performed by transient analysis and fluid-structure interaction analysis. As a result, this study will give a opportunity for efficient design of sonar dome without high cost and time consumption.
이영우(Y.W. Yi),이동섭(D.S. Lee),신구균(K.K. Shin),홍진숙(C.S. Hong),임희창(H.C. Lim) 한국가시화정보학회 2021 한국가시화정보학회지 Vol.19 No.3
Large Eddy Simulation (LES) has been popularly applied and used in the last several decades to simulate turbulent boundary layer in the numerical domain. A fully developed turbulent boundary layer has also been applied to predict the complicated wake flow behind bluff bodies. In this study we aimed to generate an artificial turbulent boundary layer, which is based on an exponential correlation function, and generates a series of realistic three-dimensional velocity data in two-dimensional inlet section which are correlated both in space and in time. The results suggest its excellent capability for high Reynolds number flows. To make an effective generation, a hexahedral mesh has been used and Cholesky decomposition was applied to possess suitable turbulent statistics such as the randomness and correlation of turbulent flow. As a result, the flow characteristics in the domain and fluctuating pressure near the wall are very close to those of fully developed turbulent boundary layers.