http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
EDISON_CFD : e-Science 인프라 기반의 전산유체역학 교육ㆍ연구용 시뮬레이션 소프트웨어 및 콘텐츠 개발
이성욱(S. Lee),이근배(K. B. Lee),박수형(S. H. Park),최성임(S. I. Choi),김종암(C. Kim) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.11
EDISON_CFD, an abbreviation of EDucation-research Integration through Simulation On the Net for Computational Fluid Dynamics, is a virtual organization designed to support educationㆍresearch in the e-Science environment. Our research group focuses on developing simulation software and contents based on numerical analyses. Through national research projects, many valuable R&D results have been developed in universities and research institutes. However, educational contents used for delivering advanced researches to inspire students still lack, and various nonlinear fluid dynamic phenomena make it harder to understand the physical reality intuitively. Thus, development of software and contents for effective and advanced educationㆍresearch is essential. The present work aims to establish the open platform of software and contents for online educationㆍresearch using the results of the state-of-art techniques.
이슬기(S.G. Yi),권형일(H.I. Kwon),최성임(S.I. Choi),박부민(P.M. Park),강영석(Y.S. Kang) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.5
A multidisciplinary design optimization of EAV (Electric Aerial Vehicle) propeller is carried out to maximize the efficiency of propeller performance. An objective is to minimize torque/power while maintaining a thrust level of baseline configuration at a given RPM and thus to improve propeller efficiency. Structural safety is also calculated during the design process and is ensured to satisfy a safety margin. A high-fidelity CFD and FEM-based structures computation is employed for a design. To test the accuracy of the analysis tools, a wind-tunnel test is conducted for the baseline propeller blade at operating RPM and numerical prediction is validated against experiment data. A derivative-free multidisciplinary design methodology based on the Kriging approximation model is used to achieve the design goal of minimization of torque. Design variables are mostly related to the shape of the blade and include twist distribution at eight cross sections along the blade span as well as the planform shape of the blade around tip area. Design results demonstrate a reduction of torque by almost 5% at constant thrust. Safety margin is well satisfied for a new blade.
e-Science 기반 EDISON 포탈의 항공우주분야 에어포일 공력 최적 설계 프레임워크 개발
권형일(H.I. Kwon),조영민(Y.M. Jo),이슬기(S.G. Yi),김사지(S.J. Kim),최성임(S.I. Choi) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.5
Design optimization is to find optimum of design space which is defined by design variables, using optimization algorithm. Recently, numerical design optimization including computational fluid dynamics (CFD) has been focused in not only aerospace engineering, but general engineering field because of many research and development for high performance computing. However it could hardly find the design optimization softwares and contents of which educational or research purposes in aerospace engineering. In this study, as one framework of EDISON DESIGN OPTIMIZATION, aerodynamic design optimization framework for an airfoil based on EDISON (EDucation-research Integration through Simulation On the Net) portal. As well as the softwares development, essential contents are also developed for the lecture associated with design optimization in the aerospace engineering. Software and contents on aerodynamic design optimization could be expected to be assisted in the lecture or lab..
오픈로터 소음 저감을 위한 비정상 유동 하의 강건최적설계
권형일(H. I. Kwon),최성임(S. Choi),권장혁(J. H. Kwon) 한국전산유체공학회 2014 한국전산유체공학회 학술대회논문집 Vol.2014 No.5
Robust design optimization for open rotor has been conducted. To alleviate computational burden of robust measurement in the design, Kriging surrogate model was employed to model responses. For performance evaluations of open rotor especially, unsteady flow simulation by state-of-the-art CFD technique of harmonic balance method was used, and it coupled with aeroacoustic analysis based on acoustic analogy. Thanks to the combined analysis between aerodynamic and aeroacoustic analyses, unsteady noise characteristics of the open rotor was efficiently investigated. The baseline configuration is 8×8 pusher-type of DLR CROR system, and rated condition is a cruise regime. Two types of aleatory uncertainties were modeled by probability density functions, and reflected in design variables and free-stream Mach number. The result showed that about 3dB of noise reduction was achieved, with it maintained thrust level of the baseline rotor system. Moreover, the validation of robustness for the uncertainties was performed, and showed the robust optimum rotor was more insensitive to the uncertainties than the baseline open rotor.
권형일(H.I. Kwon),이슬기(S.G. Yi),최성임(S.I. Choi),김근배(K.B. Kim) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.11
In this study, we present that multi-stage design framework for aerodynamic design optimization of rotary wing such as propeller and helicopter rotor blades. Strategy of the proposed framework is to enhance aerodynamic performance using both planform and sectional design optimization iteratively. In first stage of planform design, we used genetic algorithm and blade element momentum theory(BEMT) based on two dimensional aerodynamic database to find optimal planform variables in short time. After initial design, local flow conditions of blade sections are calculated. Next stage, sectional design optimization is conducted using two dimensional Navier-Stokes analysis and gradient based optimization algorithm. Mien optimal shapes are determined, planform design is performed again. Through the iterative design process, not only optimal flow condition but also optimal shape could be acquired. To validate the framework, design optimization for propeller which operated in electric vehicle system were performed As a results, about 8% of efficiency enhancement has acquired.
공력 향상과 RCS 감소를 고려한 무인 전투기의 형상 최적설계
조영민(Y.M. Jo),최성임(S.I. Choi) 한국전산유체공학회 2012 한국전산유체공학회지 Vol.17 No.4
Nowadays, Unmanned Combat Air Vehicle(UCAV) has become an important aircraft system for the national defense. For its efficiency and survivability, shape optimization of UCAV is an essential part of its design process. In this paper, shape optimization of UCAV was processed for aerodynamic performance improvement and Radar Cross Section(RCS) reduction using Multi Objective Genetic Algorithm(MOGA). Lift and induced drag, friction drag, RCS were calculated using panel method, boundary layer theory, Physical Optics(PO) approximation respectively. In particular, calculation applied Radar Absorbing Material(RAM) was performed for the additional RCS reduction. Results are indicated that shape optimization is performed well for improving aerodynamic performance, reducing RCS. Further study will be performed with higher fidelity tools and consider other design segments including structure.
대각 내재적 조화균형법을 이용한 헬리콥터 로터 블레이드의 비정상 공력 해석
임동균(D.K. Im),최성임(S.I. Choi),박수형(S.H. Park),권장혁(J.H. Kwon) 한국전산유체공학회 2011 한국전산유체공학회지 Vol.16 No.4
In this paper, the diagonal implicit harmonic balance method is applied to analyze helicopter rotor blade flow. The periodic boundary condition for Fourier coefficients is also applied in hover and forward flight conditions. It is available enough to simulate the forward flight problem with only one rotor blade using the periodic boundary condition in the frequency domain. In order to demonstrate the present method, Caradonna & Tungs rotor blades were used and the results were compared to the time-accurate method and experimental data.