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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Aeronautical & Space Sciences
Journal Basic Information
Journal DOI :
The Korean Society for Aeronautical & Space Sciences
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Volume & Issues
Volume 30, Issue 8 - Dec 2002
Volume 30, Issue 7 - Oct 2002
Volume 30, Issue 6 - Sep 2002
Volume 30, Issue 5 - Aug 2002
Volume 30, Issue 4 - Jun 2002
Volume 30, Issue 3 - May 2002
Volume 30, Issue 2 - Apr 2002
Volume 30, Issue 1 - Feb 2002
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Critical Angle Analysis of Elliptical Corner Cracks in Mechanical Joints by Weight Function Method and Finite Element Analysis
Heo, Sung-Pil ; Yang, Won-Ho ; Ko, Myung-Hoon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 1~9
DOI : 10.5139/JKSAS.2002.30.4.001
There is the high possibility of crack initiation from mechanical joints, which are widely used in aircraft fuselages, due to the development of stress concentration and contact pressure. In this paper, the mixed-mode stress intensity factors at the surface and deepest points of an inclined quarter elliptical corner crack in mechanical joints are analyzed by the weight function method. The coefficients included in the weight function are obtained by finite element analyses for reference loadings. Critical angle at which mode I stress intensity factor becomes maximum is determined by analyzing the variation of stress intensity factors along incline angle of crack and the effects of the amount of clearance and crack depth on the critical angle are investigated.
A Study on the Dynamic Ground Effect on Three-Dimensional Wings Using a Time Domain Panel Method
Han, Cheol-Heui ; Cho, Jin-Soo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 10~17
DOI : 10.5139/JKSAS.2002.30.4.010
A study on the dynamic ground effect on three-dimensional wings is done using an indirect boundary element method(unsteady panel method). An integral equation is obtained by applying Green's theorem on all surfaces of the fluid domain. Constant strength dipole and source panels arc distributed on a wing's surface. The wake sheet is represented by constant strength dipoles. At each time step, a row of wake panels is assumed to be convected from the trailing edge of the wing. The tip vortex behind wings in dynamic ground effect moves outward. The amplitudes of the aerodynamic coefficients for the wings in dynamic ground effect are augmented much more comparing to the case in static ground effect.
Aerodynamic Shape Optimization Using a Continuous Adjoint Formulation on Unstructured Meshes
Lee, Sang-Wook ; Kwon, Oh-Joon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 18~27
DOI : 10.5139/JKSAS.2002.30.4.018
Aerodynamic shape optimization of two-dimensional airfoils in inviscid compressible flows is performed using a continuous adjoint formulation on unstructured meshes. Accurate evaluation of the gradient is achieved by using a reconstruction scheme based on the Laplacian averaging. A least-square method with extended stencil is used for flow gradient calculations. Proper convergence criterion is studied on Euler and adjoint equations for efficient design. The present method has been applied to RAE2822 and NACA0012 airfoils such that wave drag can be minimized by removing the shock wave. An inverse design is also performed to recover the shock wave on the designed RAE2822 airfoil.
A Numerical Study on Acoustic Behavior in Combustion Chamber with Acoustic Cavity
Sohn, Chae-Hoon ; Kim, Young-Mog ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 28~37
DOI : 10.5139/JKSAS.2002.30.4.028
Acoustic behavior in combustion chamber with acoustoc cavity is numerically investigated by adopting linear acoustic analysis. Helmholtz-type resonator is employed as a cavity model to suppress acoustic instability passively. The tuning frequency of acoustic cavity is adjusted by varying the sound speed in acoustic cavity. Through harmonic analysis, acoustic pressure responses of chamber to acoustic oscillating excitation are shown and the resonant acoustic modes are identified. Acoustic damping effect of acoustic cavity is quantified by damping factor. As the tuning frequency approaches the target frequency of the resonant mode to be suppressed, mode split from the original resonant mode to lower and upper modes appears and thereby damping effect is degraded significantly. Considering mode split and damping effect as a function of tuning frequency, it is desirable to make acoustic cavity tuned to maximum frequency of those of the possible splitted upper modes.
A Study on the Measurement of Aerodynamic Load of Aircraft Wing
Kang, Seung-Hee ; Lee, Jong-Geon ; Lee, Seung-Soo ; Ahn, Seung-Ki ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 38~43
DOI : 10.5139/JKSAS.2002.30.4.038
A study on the test, design and fabrication of wind tunnel model for measurement of air load distribution on wing surfaces is presented. 447 pressure taps are installed normal to the wing surfaces, and measured by PSI-8400 system using total 8 ESPs modules installed in the model. The test was performed at 50 m/sec constant speed in the low speed wind tunnel of Agency for Defense Development. Tests were carried out to determine effects of angle of attack, angle of sideslip and flap and stores for the load distribution of wing. The test results in this paper can be applied to the design optimization of structure and validation of computational fluid dynamics.
Numerical Study on Aerodynamic Characteristics of Flapping-Airfoil in Low Reynolds Number Flows
Lee, Jung-Sang ; Kim, Chong-Am ; Rho, Oh-Hyun ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 44~52
DOI : 10.5139/JKSAS.2002.30.4.044
Aerodynamic characteristics of a flapping airfoil in low Reynolds number flows are numerically studied using the unsteady, incompressible Navier-Stokes flow solver with a two-equation turbulence model. For more efficient computation of unsteady flows over flapping airfoil, the flow solver is parallel-implemented by MPI programming method Unsteady computations are performed for low Reynolds number flows over a NACA four-digit series airfoils. Effects of pitching, plunging, and flapping motion with different reduced frequency, amplitude, thickness and camber on aerodynamic characteristics are investigated. Present computational results yield a better agreement in thrust at various reduced frequency with experimental data.
High Speed Wind Tunnel Test for the Rocket with Strap-on Boosters
Ra, Seung-Ho ; Kim, In-Sun ; Choi, Seong-Wook ; Ok, Ho-Nam ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 53~63
DOI : 10.5139/JKSAS.2002.30.4.053
The high speed wind tunnel test for the study of the basic aerodynamic characteristics of the rocket with twin strap-on boosters was performed using ADD trisonic wind tunnel on the Mach number range of 0.4~4.0. The 6 % scale model of the early design version of Korean sounding rocket was tested. The tested configurations were core only, core/fins, core/boosters and core/boosters/fins. The effects of core length, gap between core and booster, and bank angle were investigated.
Damped Vibrations of Axially-Stressed Laminated Beams using Zig-Zag Finite Element
Lee, Deog-Gyu ; Cho, Maeng-Hyo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 64~69
DOI : 10.5139/JKSAS.2002.30.4.064
Dynamic analysis of laminated beams with a embedded damping layer under tension or compression axial load is investigated. Improved Layer-Wise Zig-Zag Beam Theory and Interdependent Kinematic Relation using the governing equations of motion are incorporated to model the laminated beams with a damping layer and a corresponding beam zig-zag finite element is developed. Flexural frequencies and modal loss factors under tension or compression axial load are calculated based on Complex Eigenvalue Method. The effects of the axial tension and compression load on the frequencies and loss factors are discussed.
Experimental Study of Thermo-Flow Field in a Model Gas Turbine Combustor with Various Swirl Conditions
Ryu, Song-Youl ; Koo, Ja-Ye ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 70~76
DOI : 10.5139/JKSAS.2002.30.4.070
Characteristics of kerosine spray combustion were investigated at various swirl condition. PDPA(Phase Doppler Particle Analysis) was used to measure the droplet sizes and velocities. R-type(Platinum vs. Platinum-13%rhodium) thermocouple was used to measure the temperature of combustion flow field inside model combustor. A visualization of spray and flame was performed with still camera. As swirl number increases due to increase of swirl vane angle, the spray and the flame were developed to radial direction rapidly. When swirl number is small, the configuration of flame is cone type, but swirl number is large, the configuration of flame is cylindrical type due to enhanced mixing by the transport of swirl momentum.
A Computational Study on the Performance Prediction of the Two-Stage Axial Compressor
Choi, Chang-Ho ; Kim, Jin-Han ; Yang, Soo-Seok ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 77~83
DOI : 10.5139/JKSAS.2002.30.4.077
A computational study on the performance prediction of a two-stage axial compressor has been performed. A quasi-steady mixing-plane method is used on the rotor/stator interface to simulate the unsteady interaction phenomena. Detail flow mechanisms, for example, choke, stall, shock/boundary interaction, etc., have been observed and discussed in conjunction with performance characteristics. Calculational data agree reasonably well with the experimental data in terms of the performance characteristics showing the applicability of computational methods to the design validation of multistage axial compressors instead of experimental methods. But it is found that the stall margin of the original compressor was rather small, thus the design modification adopting a simple 1D/2D method has been conducted and its corresponding computations are also carried out. As a result of the redesign process, the stall margin becomes wide enough, but the overall performance is unsatisfactory, therefore, it seems that the redesign of the blades using 3-D methods is needed in the future work.
Characteristics of Side force using Jet Vanes in a Shroud
Sung, Hong-Gye ; Hwang, Yong-Seok ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 84~91
DOI : 10.5139/JKSAS.2002.30.4.084
Thrust vector characteristics of jet vanes installed in a shroud are very unique and much more complicated than those of the jet vane acting without any shroud by the fact of additional physical phenomena. The fluid dynamic interferences induced by jet vanes and shroud as well as jet vane's aerodynamic performance are investigated to characterize thrust vector control by semi-empirical model, three dimensional numerical analysis including real complex geometry, and ground firing test of real motors.
Maximum Launch Range and F-pole Evaluation For Semi-Active Radar Missile
Kwon, Ky-Beom ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 92~98
DOI : 10.5139/JKSAS.2002.30.4.092
In this study, maximum launch range and F-pole are evaluated and analyzed for the semi-active radar missile concerning various launch condition, performance limitation and target maneuvers. Furthermore, general evasion maneuvers are considered when shooter approaches to target with head-on conditions. A point-mass target, shooter and missile model is used including aircraft and missile dynamics. More realistic missile motion simulation is conducted using aerodynamic performance data, geometry, performance limitation, radar seeker performance and so on. Maximum launch range, which is the distance for intercept satisfying target and missile motion and performance, is evaluated using root finding method. F-pole, which is the distance between target and shooter when intercept is completed, is evaluated assuming that shooter maneuvers through pursuit guidance to target.
A Study of the One-Stage Axial Turbine Performance with Various Axial Gap Distances between the Stator and Rotor
Kim, Dong-Sik ; Cho, Soo-Yong ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 99~105
DOI : 10.5139/JKSAS.2002.30.4.099
The performance test of an axial-type turbine is carried out with various axial gap distances between the stator and rotor. The turbine is operated at the low pressure and speed, and the degree of reaction is 0.373 at the mean radius. The axial-type turbine consists of ons-stage and 3-dimensional blades. The chord length of rotor is 28.2mm and mean diameter of turbine is 257.56mm. The power of turbo-blower for input power is 30kW and mass flow rate is
/min at 290mmAq static-pressure. The RPM and output power are controlled by a dynamometer connected directly to the turbine shaft. The axial gap distances are changed from a quarter to three times of stator axial chord length, and performance curves are obtained with 9 different axial gaps. The efficiency varies about 8% of its peak value due to the variation of axial gap on the same non-dimensional mass flow rate and RPM, and experimental results show that the optimum axial gap is 1.6-1.9Cx.
Optimization of Spacecraft Structure by Using Coupled Load Analysis
Hwang, Do-Soon ; Lee, Young-Sin ; Kim, In-Gul ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 106~113
DOI : 10.5139/JKSAS.2002.30.4.106
In spacecraft system, structure subsystem has the mission of supporting all the components safely under various space environmental conditions. The safety of spacecraft structure is finally verified from the coupled load analysis, which is a branch of load analysis which combines the launch vehicle and satellite. This study introduces the optimization algorithm to reduce the weight of spacecraft structure under launch environmental conditions directly. The acceleration responses are obtained by the introduction of coupled load analysis, which lead to check the failure of spacecraft structural members. The results show a 12% saving of structural weight and this saving is mainly driven by the thickness of honeycomb core, which strongly affects the natural frequencies of platforms and panels.
An analysis on the ground impact load and dynamic behavior of the landing gear system using ADAMS
Choi, Sup ; Lee, Jong-Hoon ; Cho, Ki-Dae ; Jung, Chang-Rae ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 114~122
DOI : 10.5139/JKSAS.2002.30.4.114
The integration of the landing gear system is a complex relationship between the many conflicting parameters of shock absorption, minimum stow area, complexity, weight and cost. Especially ground impact load and dynamic behaviors greatly influence design load of landing gear components as well as load carrying structural attachment. This study investigates ground impact load and dynamic behaviors of the T-50 landing gear system using ADAMS. Taking into account for various operational/environmental conditions, an analysis of shock absorbing characteristics at ground impact is performed with experience derived from a wide range of proprietary designs. Analytical results are presented for discussing the effects of aircraft horizontal and vertical speed, landing attitudes, shock absorbing efficiency. This analysis leads us to the conclusion that the proposed program is shown to be a better quantitative one that apply to a new development and troubleshooting of the landing gear system.
Uncertainty Analysis for Subsonic Wind Tunnel Testing
Kwon, Ki-Jung ; Sung, Bong-Zoo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 123~130
DOI : 10.5139/JKSAS.2002.30.4.123
Aerodynamic results for an airplane model produced in a subsonic wind tunnel testing inadvertently include errors which are added during model preparation, data acquisition, manipulation, and/or describing the results. Predicting or analyzing uncertainty for the final results is necessary for trusting them and for applying them to real airplane. This paper describes the analytic and systematic method for calculating and describing the uncertainties of aerodynamic coefficients.
Grid Computing and duster Technology
Cho, Kum-Won ; Lee, Sang-San ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 131~144
DOI : 10.5139/JKSAS.2002.30.4.131
The Current and Future of UCAV Systems -Part 2
Lee, Kyung-Tae ; Kim, Jung-Yub ; Lee, Ki-Hak ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 4, 2002, Pages 145~159
DOI : 10.5139/JKSAS.2002.30.4.145