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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
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Journal DOI :
The Korean Society for Aeronautical & Space Sciences
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Volume & Issues
Volume 27, Issue 8 - Dec 1999
Volume 27, Issue 7 - Nov 1999
Volume 27, Issue 5 - Aug 1999
Volume 27, Issue 6 - 00 1999
Volume 27, Issue 4 - 00 1999
Volume 27, Issue 3 - 00 1999
Volume 27, Issue 2 - 00 1999
Volume 27, Issue 1 - 00 1999
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Modification of Tip Vortex by Spanwise Slots
Han, Yong-Oun ; Bae, Hwang ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 1~1
Characteristics of trailing vortices generated by a rectangular fixed wing with the NACA23012 airfoil section have been investigated with a 2-dimensional LDV system. Curved slots were imbedded near the rectangular tip to blow a slight amount of the main stream into the tip face and to modify tip vortices. Tangential and axial velocity components of tip vortices, circulations and momentum deficits were measured at vertical planes to the vortex trail for both the plain and the slotted wings, respectively. Lift distributions over both wings were also investigated by the use of the bound dirculations measured at five different locations for each span. It was found that the slotted wing develops a fairing effect at the tip and lessens the vortex strengths without serious defects for the lift losses even though the slight momentum deficit was perceived for this selected model. It was, therefore, confirmed that the slotted wing can be used for a device to improve the aerodynamic performance by the tip vortex modification.
Application of Autoregressive Method to the Spectral Analysis of Turbulent Flow Signal
Jung, Yong-Wun ; Park, Seung-O ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 8~8
Autoregressive method for the spectral analysis of turbulent flow signal is discussed in this paper. When small samples are available owing to the record length or the limited memory size of experimental device or inherent characteristics of flow signal, the AR method is more useful than the FFT method for spectral analysis, because its resolution is independent of the size of data samples. Especially, low frequency characteristic is much better analyzed by the AR method. To illustrate the advantages of the AR method, some typical signals often encountered in turbulent flows are analyzed using the AR method.
Unburned Gas Turbulence Properties in Turbulent Premixed Flame
Lee, Dae-Hoon ; Kwon, Se-Jin ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 17~17
Measured turbulence properties of methane/air premixed flame was presented. Two-color laser velocimeter was used to obtain simultaneous statistics of vertical velocity components of open jet burner within unburned gas region. Same set of measurements was repeated at 21 locations to investigate the spatial variation of the turbulence properties. Test condition was at Reynolds number of 7,000 and fuel equivalence ratio 0.6 and 1.0. Time records of instantaneous velocities were reduced to obtain mean velocities, Reynolds stress, probability densities, and joint probabilities. The flame affected all the turbulence properties in the unburned gas region. The finding strongly suggests that volume expansion at the flame surface is responsible for the changes in turbulence properties. Present finding also implies that the existing models assuming invariant turbulence properties can be improved by accounting for this effect.
Aerodynamic Noise Generated by an Upright Wall-Mounted Half Cylinder
Lee, Seung-Bae ; Choe, Jong-Su ; Han, Jae-O ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 24~24
The turbulent flow approaching an upright wall-mounted half cylinder has been numerically investigated by using the Large-Eddy Simulation. The formation and the downstream transport of horseshoe vortex are numerically simulated and compared with experimental data which are measured in an anechoic wind tunnel. The interactions between the horseshoe vortex formed by re-orientation of incoming vorticity and the Strouhal vortices in the near wake of the half cylinder are investigated in this study. The governing equations are formulated in terms of a structured, curvilinear grid system to accommodate the truncated deductive model for the subgrid-scale turbulent motions, The present results are produced at two Reynolds numbers of
, based on the cylinder diameter by changing the incoming boundary layer thickness
. The far-field sound is computed using Ligthill's acoustic analogy. The results are represented in terms of the flow characteristic values such as time mean base pressure coefficients, vortex shedding frequencies.
An Experimental Study of Tip vortex Roll-up of an Oscillating Wing, Part I : Mean Velocity Field
Chang, Jo-Won ; Park, Seung-O ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 36~36
An experimental study was carried out to examine quantitatively the tip vortex roll-up in the near-field of an oscillating wing. A NACA 0012 rectangular planform wing with an aspect ratio of 4.0 was mounted on the floor of the wind tunnel test section, and the wing was sinusoidally pitched about the quarter chord. Both the mean incidence angle and the amplitude of oscillation were set at
, which made the angle of attack vary from
. The flow visualization and measurements were made for the case of K=0.09, and
. Measurements by using the triple hot-film probe were carried out at two downstream stations: X/C=0.5 and 1.5. The streamwise flows for the pitch-up motion remained attached and resulted in well-defined circular vortex cores, while those for the pitch-down motion were separated to yield irregular and turbulent cores. The phase-averaged mean velocity profiles were distinctly different from each other at the same instantaneous angle of attack for pitch-up and pitch-down motions. The flow field of pitch-down motion was strongly influenced by massive separation, and hence the differences among various flow quantities for pitch-up motion and those for potch-down motion were severer. The phase-averaged velocity fields in the wing tip vortex region are presented and variations with respect to the instantaneous angle of attack are discussed.
A Study on the Cure Characterization of Hercules AS4/3502 Prepreg
Chung, Suk-Choo ; Kang, Moon-Koo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 47~47
Cure characterization was peformed for the Hercules AS4/3502 prepreg which is one of the most popular carbon reinforced polymeric composite material. In order to curve fit the non-isothermal curing of the given material more accurately, a modified autocatalytic model was used. The used model describes the curing behavior of the AS4/3502 accurately, while it incorporates the least number of model constants. The experimental data obtained in this study can be used in the analysis and optimization of the manufacturing process using the given prepreg.
Vibration Control of Flexible Beam under Random Base Excitation
Cho, Yun-Hyun ; Heo, Hoon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 52~52
A control strategy for a dynamic system under irregular disturbance by using
is developed and investigated via experimental simulation. In order to design Heo stochastic controller system equation is transformed to stochastic domain by F-P-K approach from physical domain. A Heo stochastic controller is designed in stochastic domain by using hewn method like PID controller. The paper is consisted of basic description of F-P-K equation approach, design of Heo stochastic controller, numerical simulation and experiments. Base excited beam and is adopted as experimental model, Heo-PI controller is designed and implemented to the system. The result reveals promising performance of the Heo stochastic controller.
A Study on the analysis of fuel sloshing in a liquid propellant tank and optimum design of ring baffles
Yoo, Joon-Tae ; Yeon, Jeong-Heum ; Youn, Sung-Kie ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 60~60
In this study, sloshing analysis and optimum ring baffle design are studied. Sloshing in axisymmetric tank of arbitrary shape is modeled by spring-mass-damper model. Sloshing analysis results for tanks in various shape are verified by comparing the results with those obtained from references and commercial code(MSC/NASTRAN). Optimum ring baffle design is also studied. An algorithm is developed with which optimum ring baffle locations and width can be obtained. In this algorithm the lateral force for a given lateral acceleration history is minimized.
The Effect of Frequency Ratio Change due to Structural Nonlinearities on Aeroelastic Responses of Two Degree of Freedom Airfoil System
Choi, In-Ho ; Kim, Dong-Hyun ; Lee, In ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 71~71
Aeroelastic analysis of two degree of freedom airfoil system with structural nonlinearities is performed. The considered structural nonlinearities are freeplay, friction, hardening bilinear, and softening bilinear nonlinearities in pitch or plunge degree of freedom. And, the case containing freeplay and friction nonlinearities in both the pitch and plunge degree of freedom is considered. Subsonic DHM and supersonic DPM are used for the unsteady aerodynamic analysis. Frequency domain analysis is performed using describing Emotion and V-g method. And time domain analysis is also performed using rational function approximation. Response characteristics are investigated for the change of the frequency ratio(the ratio of plunging frequency to pitching frequency).
Aircraft Design Optimization Using Quasi-Procedural Data Management Method
Chun, Sung-Jin ; Lee, Dong-Ho ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 81~81
An aircraft conceptual design optimization system with flexibility and extensibility has been developed using Quasi-Procedural data management method combined with Object Oriented Programming method. System The design database management system automatically manages design data linkage between analysis modules and consistency between them. Consistency maintenance mechanism reduces computational cost of design optimization through removing redundant computation time and executing required analysis modules only. Sensitivity analysis function in design system can help designers choice of design variable and 3-D graphical visualization of ai craft configuration can help designers decision on target design. Adding or removing constraint or objective variables and analysis codes is very easy in current design system architecture and assist designers improvements or change of design optimization strategy.
Maneuvering Target Tracking Using Error Monitoring and Recovery Technique in Cluttered Environment
Choi, Jae-Weon ; Fang, Tae-Hyun ; Hong, Keum-Shik ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 90~90
This paper presents an improved version of the IMMPDA(interacting multiple model with probabilistic data association) filter with the detecting capability of a maneuver. In order to detect a maneuver of a target, an error monitoring and recovery method of perception net is employed for the IMMPDA filter design. The PDA(probabilistic data association) filter, which is only slightly more complex than a standard filter, can be combined with the IMM(interacting multiple model) algorithm for tracking in a cluttered environment. Both detecting a maneuvering target and compensating the estimated state can be achieved by employing the properly implemented error monitoring and recovery technique. Thus, the proposed method is derived as an extension of the previous result on tracking for a maneuvering target without clutter. The conventional IMMPDA filter which employing the error .monitoring and recovery technique shows good tracking performance for a highly maneuvering target as well as it reduces maximum values of estimation errors when the maneuver starts and finishes. The effectiveness of the proposed method is validated through simulations by comparing it with the conventional IMMPDA filter.
Controller Design of a Flexible Launch Vehicle Using Co-Evolutionary Augmented Lagrangian Method
Hwang, Jae-Won ; Lee, Ho-Il ; Tahk, Min-Jea ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 102~102
A number of algorithms have been proposed to solve constrained optimization problem using evolutionary computation methods. However, most of them have not been useful when addressing heavily constrained optimization problems in terms of computational efficiency and solution accuracy. These algorithms have mostly been applied to evolution of single group. In this paper, we propose a new co-evolutionary algorithm based on the augmented Lagrangian methods. The proposed method is based on the evolution of two groups with opposite objectives. One group by to minimize the object parameters, the other try to maximize the Lagrange multipliers. Then the optimal solution is saddle point. The proposed method is applied to the autopilot design of a flexible launch vehicle problem.
A Study on Ground Verification TESTBED for Three Axis Attitude Control of Satellites - Part I. Development Study
Park, Young-Woong ; Han, Jung-Youp ; Bang, Hyo-Choong ; Park, Bong-Kyu ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 113~113
A study on the development of spacecraft attitude control system using a 3 axis spacecraft attitude control ground testbed is discussed in this paper. The testbed structure is made of aluminum structure with a configuration for general satellites. The testbed is connected to an air bearing for the 3 axis attitude control and some panels are located in the testbed holding experimental equipments. Experimental equipments are connected by wires to transfer power and signal. An OBC(On Board Computer) is used as a controller with on-board signal processing software developed. RF modems are installed between the testbed and a PC used as a ground station. Telemetry & command data processing software is also designed.
Design of GPS Augmentation System for CAT-II Landing at Inchon and Kimpo International Airports
Sim, Sung-Bo ; Won, Yu-Doo ; Cho, Wan-Hee ; Lee, Young-Jea ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 122~122
A standalone CPS cannot be used for CAT-I, II, and III aircraft landing application. Additional ranging signals from pseudolites on the ground make VDOP (vertical dilution of precision) and HDOP (horizontal dilution of precision) lower and at the same time deliver DCPS error correction information to the user aircraft around airport area. As a result, pseudolites as a CPS augmentation system improves accuracy, integrity, and availability of augmented CPS system. In this paper, based on minimizing the worst case CPS satellite outage, the location of multiple pseudolites was determined. And the location for five pseudolites was determined by VDOP and HDOP at Inchon and Kimpo International Airports
Dynamic Error Analysis of a Dynamically Tuned Gyroscope Related on the Characteristics of Gimbal Suspension
Rhim, Jae-Wook ; Moon, Hong-Key ; Oh, Moon-Su ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 133~133
The effect of suspension characteristics on dynamic behavior of dynamically tuned gyroscopes(DTG) is investigated and a design strategy for performance improvement is presented in this study. For this, rather than analyzing the suspension system as a whole, major parts are analyzed individually and the system characteristics are built up based on the individual results. This approach makes it easier to understand the role of each design parameter in the suspension system. The result of this study shows that the stiffness coupling of suspension system and the flexibility of flexure-column significantly affects the performance of DTG.
Quantitative Assessment of Solid Propellant Smoke with AGARD Smoke Classification
Park, Young-Kyu ; Yoo, Ji-Chang ; Kim, In-Chul ; Lee, Tae-Ho ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 144~144
The degree of smoke formation by the combustion gases of ten kinds of double base and composite solid propellants were classified by AGARD smoke classification method for the purpose of assessing the smoke properties of solid propellants quantitatively and investigating the effects of the propellant formulations on smoke formation phenomena. Smoke was measured experimentally under the various climatic conditions controlled in the Smoke Chamber for the smoke classified propellants. Measured results were compared with the classified results for considering practical use of the smoke classification method.
Structural Analysis of Simplified Composite Wing Box
Koo, Kyo-Nam ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 156~156
This paper describes the finite element model of a simplified composite wing box analysis method for sizing its structural parts. The results of NASTRAN execution were post-processed to obtain internal loads and strains for critical load. The size from the preliminary initial sizing stage was updated according to the reserve factor after running the 1st finite element model. The updated size was used as an input data for the 2nd finite element model to check strength. The final size was determined so that all the structural parts have reserve factor over 1.0.
Orbit and Attitude Control Requirement Analysis of KAISTSAT-4
Kim, Byung-Jin ; Seon, Kwang-Il ; Tahk, Min-Jea ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 165~165
Aircraft Landing System Using GPS
Kee, Chang-Don ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 5, 1999, Pages 173~173