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A STUDY ON THE LOW REYNOLDS NUMBER AIRFOILS FOR THE DESIGN OF THREE DIMENSIONAL WING
K.J. Jung(정경진),J. Lee(이재훈),J.H. Kwon(권장력),I.M. Kang(강인모) 한국전산유체공학회 2009 한국전산유체공학회 학술대회논문집 Vol.2009 No.4
In this study, a generic airfoil designed by the inverse method was evaluated with several candidate airfoils as a first step. Each airfoil was compared with respect to aerodynamic performance to meet the requirement of HALE(high altitude long endurance) aircraft. The second step was to optimize the candidate airfoil using the couple of optimization formulations to down select an optimum airfoil. For the analysis of low Reynolds number 2D flow, Drela's MSES was used. After comparing the aerodynamic results, the best airfoil was chosen to construct the baseline 3D wing. The Navier-Stokes code was used to evaluate the overall aerodynamic performance of designed wing with other wings. The results show that the designed wing has the best performance compared with other wings.
정경진(K. J. Jung),이재훈(J. H. Lee) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.11
A flap acts as a control surface or a high-lift device. The prediction of its aerodynamic performance is important in the development of aircraft and it is usually conducted with wind tunnel tests. To investigate the usefulness of numerical methods, the aerodynamic characteristics of a low aspect ratio wing are analyzed with numerical methods. The wing has an unswept untapered planform and a plane flap near the trailing edge. The wing configuration and experimental data are from the NACA report. The considered numerical methods include panel methods and computational fluid dynamics. The results of aerodynamic analysis of each numerical method are compared with experimental data.
정경진(K.J. Jung),이재훈(J.H. Lee),강인모(I.M. Kang) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.5
Icing is one of the most serious hazards for aircraft. The amount and rate of icing depend on a number of meteorogical and aerodynamic factors. Of primary importance are amount of liquid water content of droplets, their size, the temperature of aircraft surfaces, the collection efficiency, and the extent of supercooled droplets. In this study, in-flight icing analysis of low reynolds number high aspect ratio wing is carried out by using FENSAP-ICE. Each liquid water contents with altitude is obtained from FAR 25 Appendix-C. And the collectoin efficiency is calculated to check out the ice accretion position of wing with two angles of attack. The degradation of aerodynamic characteristics of aircraft are figured out by investigating the accretion of rime and glaze ice.
액적입사 분석을 통한 결빙감지 센서 장착을 위한 기법 연구
정경진(K. J. Jung),강인모(I. M. Kang),류태규(T. K. Reu) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.11
Icing is one of the most serious hazards for aircraft. In order to protect an aircraft from ice accretion, it is necessary to determine when aircaft is flying in icing conditions. Ice detectors automatically determine if the aircraft is in such conditions in order to trigger ice protection systems. In this study, shadow zones which correspond to areas where ice detectiors do not effectively retister ice was identified by the droplet impingement analysis. In-flight icing analysis of fuselage wiht tail configuration was carried out by using FENSAP-ICE. Each liquid water contents with altitude variations while the aircraft is in climb condition is obtained from FAR 25 Appendix-C. And several candidate locations of ice detector was investigated to figure out the proper position in order to ensure that ice detectors will function properly.
여정수(J . S . Yeo),정일정(I . C . Cheong),정경진(K . J . Chung),정선부(S . B . Chung),정연후(Y . H . Jung),이기복(K . B . Lee),설동섭(D . S . Sul),오봉국(B . K . Ohh) 한국축산학회 1990 한국축산학회지 Vol.32 No.9
Through chromosomal analysis of 109 heads of the Korean Native Cattles, this research was observed results as follows; 1. Six heads(5.5%) were cosisted of two kinds of mosaic chromosomal spreads( I : monosomy, normal and trisomy II: monosony and normal) and these mosaicsms were variated at #29 chromosome. 2. One head was showed supernumery chromosome suggested B-chromosome. 3. 1/29 Robertsonian translocation was not found in the Korean Native Cattles.
RANS 모델링을 이용한 Hump 형상의 박리 유동에 대한 연구
이재훈(J. Lee),배중헌(J.H. Bae),정경진(K.J. Jung) 한국전산유체공학회 2017 한국전산유체공학회지 Vol.22 No.1
In this paper, separated flow characteristics is studied using the RANS(Reynold-averaged Navier-Stokes) modeling. The analysis is performed for the NASAs hump configuration which is the combination of a flat plate and a hump. This configuration was used in NASAs flow control workshop and it was one of validation cases for RANS and LES simulations. The separation occurs at the 65% of model length where a slot is positioned for the flow control. No flow control case and steady suction case are studied using RANS modeling. The Spalart-Allmaras model and the SST(Shear Stress Transport) model are applied and their accuracy are compared. To correlate CFD analysis with experimental data, the optimal boundary condition was investigated and the effect of a cavity around the slot is studied for the no flow case.
이재훈(J. Lee),정경진(K. Jung) 한국전산유체공학회 2016 한국전산유체공학회지 Vol.21 No.1
One of the obstacles on the grid generation for complex geometries with multi-block structured grids is the domain decomposition. In this paper, the domain decomposition for two-dimensional flow is studied using the flow characteristics. The potential flow equation with the source distribution on the panel surface is solved to extract the information of the flow. The current approach is applied to a two-dimensional cylinder and Bi-NACA0012 problems. The generated grids are applied to generic flow solvers and reasonable results are obtained. It can be concluded that the current methods is useful in the domain decomposition for the multi-block structured grid.
고받음각 델타익 유동의 와류 붕괴 모사를 위한 DES 해석
사정환(J.H. Sa),손미소(M. Son),박수형(S.H. Park),구기범(G. Gu),김민아(M. Kim),정경진(K.J. Jung) 한국전산유체공학회 2013 한국전산유체공학회 학술대회논문집 Vol.2013 No.5
Detached Eddy Simulation(DES) is performed to understand vortex breakdown of a high-angle-of-attack Delta Wing flow. The fifth-order Upwind method is used to reduce turbulent dissipation. The computational results(DES) on ONERA Delta Wing model with a 70° sweep angle are compared with unsteady Reynolds-averaged Navier-Stokes(RANS) results and experimental data for validation with pressure distribution, surface pressure coefficient contour, and streamline distribution.
천이 SST 난류 모델을 이용한 3차원 날개 공력 해석
이재훈(J. H. Lee),정경진(K. J. Jung) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.11
In this study, aerodynamic coefficients are computed with the transition SST turbulence model for a three-dimensional wing. The transition SST turbulence model solves two additional transport equations to reflect the effect of the transition. Using this model, the three-dimensional wing of an aerial vehicle is solved, and their results are compared with other turbulence model. According to the numerical tests, the transition SST model predicts lower viscous drag which is resulted from the transition. Therefore, this model will be useful in the design of airfoils and wings in the transitional flow.