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허도영(Doe Young Hur),이동현(Donghyun Lee),송봉하(Bongha Song) 한국자동차공학회 2014 한국자동차공학회 부문종합 학술대회 Vol.2014 No.5
During the age of fuel economy, aerodynamic efficiency of ground vehicles takes more portion than ever. But aero items, or enablers, are limited because of many reasons. Thus improving the efficiency of current enablers is one of the most important issues to increase aerodynamic performance of the ground vehicles. In this paper, I will discuss about the efficiency of hood deflector. The part can change the whole aerodynamic characteristics of a ground vehicle, both drag and lift, with little change of its shape. Aerodynamic benefit by hood deflector affects drag coefficient reduction. 0.01 drag reduction is generally regarded as 0.2mpg fuel save. Thus by only adding or modifying the hood deflector, more than 1mpg of fuel efficiency can be improved. Furthermore, if the shape of the parts can be optimized, aerodynamic characteristics can be largely changed. To build or optimize 3-Dimensional shape of vehicle, millions of approximated points are needed. But optimizing a number of points is inefficient and almost impossible. So by using improved Vehicle-modeling function, can improve design efficiency for automobiles and other complex systems. Through control poles and various methods of superposition, the complex shape of a large-scale system can be defined by a set of spline curves by Bezier curves. To facilitate shape optimization, methods of shape representation have been widely investigated. As a result, an increase in the number of superposition functions occurs. To resolve this issue, Kulfan and Bussoletti represented the shape information of an object by exponential functions instead of a set of points to control streamline curves, and applied this method to the shapes of 2D wings, 3D wings, and aircraft bodies. For Vehicle Modeling Function for hood deflector, total 10 variables are defined. Using D-optimal DOE method, total 98 cases are defined. The optimized models successfully showed improvement of aerodynamic characteristic of the vehicle. For further study, an optimization tool should be developed to adapt the hood deflector to other kinds of vehicles.
고고도 장기체공 항공기 날개의 다목적 최적화를 이용한 공력-구조 동시 설계
김정화(JeongHwa Kim),전상욱(Sangook Jun),허도영(Doe Young Hur),이동호(Dong-Ho Lee) 한국항공우주학회 2011 韓國航空宇宙學會誌 Vol.39 No.1
본 연구에서는 고고도 장기 체공 항공기 날개의 스팬과 주날개보의 형상을 설계변수로 동시에 고려하는 공력-구조 동시 설계를 수행하였다. 이 때 공기역학적 성능 최대화와 중량 최소화를 한 번에 수행하기 위해 다목적 최적화를 이용하였다. 설계 대상이 된 날개는 구조적 대변형이 발생되므로 전산유체역학과 유한요소법을 이용하여 비선형 정척 공탄성 해석을 수행하였다. 설계를 위한 해석에 요구되는 계산 비용을 감소시키기 위해 반응면을 구성하였으며 이를 위해 실험계획법이 이용되었다. 또한 본 연구에서는 대변형이 발생되지 않은 형상과 대변형이 발생한 형상의 공력 성능을 비교하여 대변형이 발생하는 경우 설계를 위해 반드시 변형이 고려되어야 함을 검증하였다. In this study, simultaneous aero-structural design was performed for HALE aircraft wing. The span and the shape of main spar were considered as design variables. To maximize aerodynamic performance and to minimize weight, multi-objective optimization was used. Nonlinear static aeroelastic analysis was performed to compute large deflection of wing. Design of experiment and response surface method were used to reduce computation cost in the design process. Also, aerodynamic performances of deformed wing and rigid wing were compared.
단면적 크기의 변화에 따른 고속열차의 터널 주행 특성에 관한 수치적 연구
곽민호(Kwak Min-Ho),노주현(Rho Joo-Hyun),윤수환(Yun Su-Hwan),박훈일(Park Hoon-Il),허도영(Hur Doe-Young),이동호(Lee Dong-Ho),권혁빈(Kwon Hyeok-Bin) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.11월
Aerodynamic characteristics of high speed train which travel through tunnel are analyzed by numericl method under tunnel's cross sectional area variation. At train's speed 300, 350, 400㎞/h, Axisymmetric numerical analyses are performed using Korean next generation high speed train HEMU-400x model and G7 model. The tunnel cross sectional areas have been investigated starting from the standard value of Seoul-Busan high speed line. As a result, the maximum value of the pressure variation inside the train is affected by the blockage ratio more, whereas the maximum value of the micro-pressure wave is affected by the train nose shape. The research result can be used as a guideline of another developments of high-speed trains and tunnel in the future.