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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.
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.
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.
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.
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.
개선된 천이 전달 방정식을 사용한 3차원 천이 유동해석
사정환(J. H. Sa),전상언(S. E. Jeon),박수형(S. H. Park),정경진(K. J. Jung) 한국전산유체공학회 2014 한국전산유체공학회 학술대회논문집 Vol.2014 No.5
The crossflow effect was considered on crossflow transition. The original γ-Re<SUB>θ</SUB> transition model was applicable 3 dimension transition analysis, but this transition model was not enough considering crossflow effect. In the present study, improved transition transport equation was developed for simulating 3 dimension crossflow transition phenomena in infinite swept wing configuration. The experimental data using infinite swept wing were used for comparison with numerical results for crossflow transitional flow. The infinite swept wing consisted of NLF(2)-0145 airfoil and 45° sweep angle. The swept wing was tested at ?4° angle of attack and Reynolds numbers from 1.92×10<SUP>6</SUP> to 3.73×10<SUP>6</SUP>. The measured transition locations compared remarkably well with computations using improved transition transport equation for all investigated flow cases.
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.
모멘트 기법과 PARSEC 함수를 이용한 에어포일 신뢰성 기반 최적설계
이재훈(J. Lee),강희엽(H. Kang),권장혁(J. Kwon),곽병만(B. Kwak),정경진(K. Jung) 한국전산유체공학회 2012 한국전산유체공학회지 Vol.17 No.2
In this study, the reliability-based design optimization of the airfoil was performed. PARSEC function was used to consider the uncertainty of the aerodynamic shape for the reliability-based shape optimization of airfoils. Among various reliability analysis methods, the moment method was used to compute the probability of failure of the aerodynamic performance. The accuracy of the reliability analysis was compared with other methods and it was found that the moment method predicts the probability of failure accurately. Deterministic and reliability-based optimizations were performed for the shape of the airfoil and it was demonstrated that reliability-based optimum assures the aerodynamic performances under uncertainties of the shape of the airfoil.
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.