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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
Editor in Chief :
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
Selecting the target year
A Study of Aerodynamic Coefficients Computation on Overlapped Grids
Jo, Geum-Won ; Gwon, Jang-Hyeok ; Lee, Seung-Su ; Park, Min-U ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 1~1
A method is developed to compute aerodynamic coefficients on structured overlapped surface grids. The structured non-overlapped surface grids with minimal gaps are constructed using a cut algorithm which is devised in this paper. The construction of minimal gaps are critical to accurately compute the aerodynamic coefficients. The resultant gaps are filled with unstructured grids which are strings of triangular cells that conform the original surface. A hybrid composite surface grid is formed which consists of non-overlapped quadrilaterals and triangles, where the quadrilaterals are the un-blanked structured cells in the original surface grids and the triangles are the newly generated triangular cells using boundary points of the un-blanked structured grids in the gaps. The flow variables which are known at the hybrid surface cells are used in computing of the aerodynamic coefficients. To validate the present procedure, a steady ONERA M6 wing and the unsteady Eglin Wing/Pylon/store test case we chosen.
Accuracy Study of the Estimated Lateral and Directional Stability Derivatives from Flight Test Data
Hwang, Myoung-Shin ; Lee, Jung-Hoon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 9~9
Lateral and directional aerodynamic parameters are estimated from flight test data of a general aviation aircraft ChangGong-91 The output error method, which is a maximum likelihood estimation technique and considers measurement noise only, is applied to analyze the aircraft response to the separate multi-step control input of rudder and aileron. The results are compared with wind tunnel test data and similar aircrafts' data. The accuracy of estimated results are validated through engineering judgement, scatter and Clamor-Rao bound.
The Study on the Boundary Layer Removal Techniques using Tangential Wall Jet Blowing
Oh, Se-Jong ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 17~17
An analytical, parameter study has been conducted to remove the boundary layer along the wind tunnel walt by using tangential wall jet. The turbulent wall jet model developed previously, has been applied to remove the boundary layer with the concept of entrainment effects of turbulent flow. The momentum and mass coefficients of the wall jet and the upstream boundary layer thickness have been chosen for the parameters. The general trends for the wind tunnel wall opening to remove the upstream boundary layer, is as expected such that the opening distance is reduced with increment of the momentum and mass coefficients, while large upstream boundary layer thickness requires larger wall opening. The analytical results are confirmed through numerical experiments. Current study can provide the data base for the wind-tunnel experiments with ground effects.
Experimental Study on the Near Field Structure of the Wing-tip Vortex
Oh, Se-Jong ; Jung, Sang-Jun ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 24~24
The Structure and development of wing-tip vortex in the near field of the downstream of the wing have been investigated. Experiments have been performed for the rectangular wing with NACA 6409 airfoil cross-section. The flow field of the vortex was measured with a spherical type five-hole probe from 0.1c to 2.0c behind the trailing edge. It has been known that in the near field the vortex flow is composed of inner viscous core, spiral out, tightly wound spiral, and the external potential vortex region. These structure have been confirmed through the experiments. The axial and tangential velocity components and the total pressure have been studied to analyze the vortex structure. These properties show clear variation of the vortex structure, vortex core position, and its deformation. It has been also found that the vortex core structure is closely related between axial velocity and the tangential velocity components.
Improvement of Aeroelastic and Aeromechanical Stabilities of Hingeless Helicopter Rotor Blade with Composite Flexures
Han, Chang-Heon ; Yun, Chul-Yong ; Kim, Seung-Jo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 33~33
In this paper, for the aeroelastic stability and the aeromechanical instabilities, called ground resonance, some experiments of small scale soft-in-plane hingeless rotor with 4blades, 2m diameter, have been carried out. To improve the aeroelastic stability of the rotor and ground resonance phenomena, the aeroelastic couplings, i.e., flap-lag coupling and pitch-lag coupling, are introduced. Blade flaring coupling is introduced by changing flexures inclination, and blade pitch-lag coupling by incorporating bending-torsion coupling of the symmetric composite layers. To represent the motion and structural stiffness of helicopter fuselage(pitch and roll) and landing gears, the gimbals are used for the numerical analysis, finite element formulation based on the Hamilton's principle is used. The blade is assumed as an elastic beam, and quasi-steady strip theory is used to obtain aerodynamic forces. Unsteady aerodynamic effects are approximately introduced through dynamic inflow model.
Thermal Stresses of FGM plate by the Galerkin-Based Green's Function
Kim, Kui-Seob ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 41~41
Nonhomogeneous materials, such as functionally graded materials(FGM), have special characteristics due to arbitrarily distributed and continuously varied material properties. For such FGM, the heat conduction equation is presented in a nonlinear form. In this paper, the temperature solution for such a nonlinear system is formulated by the Galerkin-based Green's function, and the associated thermal stress distribution is formulated under the mechanical traction-free boundary condition. The Galerkin-based Green's function solution has the advantage of the application to the boundary conditions, and the solution is accurate since it does not require the approximation of material properties. Numerical calculations are carried out for a FGM plate made of Zirconium Oxide and Titanium alloy, and the temperature and thermal stresses distributions are shown in figures.
The Enhanced Bending and Torsional Rigidity Design of a Semi-Monocoque Structure with a Large Cut-Out
Kim, Cheol ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 50~50
When a semi-monocoque shell structure stiffened by bulkheads, frames, and longerons has a large engine door cut-out on its understructure, several structural design options fastening the door panel to the shell are analyzed by using the FEM to find out the optimal design to enhance the bending and torsional rigidity of the shell. This type of structures can be easily found in the aft fuselage structure of fighter aircraft. All load-carrying structures and fasteners are replaced by NASTRAN elements, depending on several design options. The center of twist of each shell cross-section is calculated from special FEA and the flexural line is formed by connecting all twist centers. Shell bending and torsional rigidities are calculated and optimal design is determined based on the rigidity results.
A Study on the Stress Intensity Factor Calculations Using Superposition Approach and the Fatigue Crack Growth Behaviors for Stiffened Sheet Structures
Hwang, Kyung-Jung ; Kwon, Jung-Ho ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 57~57
The superposition method was introduced to calculate the stress intensity factor for center-cracked stiffened sheets of aircraft structure with center stiffener intact or broken using closed form solutions from literatures. The analysis results were verified through comparison with those of finite element analysis. And this computation procedure of stress intensity analysis was incorporated into a fatigue crack growth model and used to predict the fatigue crack growth life to evaluate the damage tolerance behaviors according to different design configurations of stiffened sheet. The analysis results of fatigue crack growth life were also compared to the experimental results.
Experimental Study on the Center Crack Repair by Composite Patch
Kim, Wie-Dae ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 71~71
This paper addresses experimental study on the fatigue life extension by using composite patch on the center-cracked panel of aging aircraft. The center crack is more often than the edge crack in aging aircraft, and the center crack study is more attractive and realistic in operational point of view. Interests are focused on the reduction of thermal residual stress caused by thermal mismatch between composite patch and aluminum. By applying composite patch, static strength and fatigue life are much improved, and lower thermal residual stress gives better fatigue life. To investigate the crack length and debonding area, ultrasonic scanning method is adopted. Adequate surface treatment between patch and aluminum is very important to produce better fatigue life preventing the bonding surfaces from debonding.
Design of Tapered Composite Laminates by Consideration of Manufacturability
Kim, Jung-Seok ; Oh, Se-Hee ; Kim, Cheol-Ung ; Kim, Chun-Gon ; Hong, Chang-Sun ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 79~79
For the design of the tapered composite laminates, a patchwise layup design method was developed. In this approach, the weight of tapered composite laminates under strength constraint was minimized and for this purpose, stacking sequences and the number of plies were optimized. The design variables were the discrete ply angles such as
and the number of plies in each patch. for the easy manufacturing and the assessment of manufacturing complexity, manufacturing cost was introduced. The composite laminates designed by patchwise layup design method were compared with the uniform thickness laminates. It showed that the optimized layup could considerably reduce total weight of the composite laminates.
Orbit and Velocity Determination of Low Earth Orbit Satellites Using Standalone GPS
Lee, Eun-Sung ; Lee, Young-Jea ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 93~93
GPS opens a new era on a positioning and timing method on the earth. It also applicable to orbit and attitude determination of satellites in space. Since altitude of GPS satellites is about 20,000km, there exists a limit in applicable satellite altitude. for LEO (Low Earth Orbit) satellites GPS is a better information source for orbit determination than other conventional range measurement devices such like a laser ranger, because large number of ground stations are not necessary for this objective. This paper is focused on orbit and velocity determination of LEO satellites using GPS. The GPS pseudoranges are the only measurement information. A LEO orbit simulator has been developed, pseudoranges with SA(Selective Availability), ionospheric error, ephemeris error, and receiver random error have been modeled. The visibility and DOP (Dilution of Precision) of GPS on the LEO orbit are surveyed. The extended Kalman filter is used for estimating 3 dimemsional position and velocity of a LEO satellite on its orbit.
Performance Analysis of the Integrated Navigation System for Space Launch Vehicle Using Piecewise Constant Measurement Noise Covariance
Park, Chan-Gook ; Kim, Tai-Hoe ; Jin, Yong ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 108~108
In this paper, it is shown that the performance of the integrated navigation system for a space launch vehicle can be improved by using well tuned measurement noise covariance considering GPS error characteristics. The integrated system consists of the strapdown inertial navigation system and GPS. The 15th error model is introduced to estimate and compensate the navigation errors using a Kalman filter. And the measurement noise covariance of the filter model is considered as a piecewise constant based on the GPS error characteristics analyzed for four trajectories of the launch vehicle. It is verified by the covariance analysis that the performance of this method has better than that of the usual method which uses the fixed measurement noise covariance.
A Study on the Relationship Between Lock-in and Coupling Function in a Ring Laser Gyro
Shim, Kyu-Min ; Chung, Tae-Ho ; Jo, Min-Sik ; Lee, Ho-Yun ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 116~116
The purpose of this paper is to research for the possibility of measuring and controlling the lock-in during the ring laser gyro operation. We analyzed the theory of the lock-in and coupling function of a dither type square ring laser gyro. We made a simulation program which can calculate the characteristic of lock-in caused by mirror scattering and by path way change, and can calculate the coupling function through the calculation of the real time value of Sagnac phase caused by the body dither. By simulation we estimated the change of the lock-in during the dither is off and coupling function during the dither is on caused by the path way change. By simulation, we estimated the variation characteristics of the maximum and the minimum lock-in values and coupling functions caused by the path way change of the ring laser which is made of different scattering mirrors. By experiment we found the periodic change of lock-in during the dither is off and coupling function during the dither is on caused by the path way change and compare their phase and period with simulation results.
Koreasat F1 & F2 Orbit Determination Performance Analysis using Flight Data
Park, Bong-Kyu ; Ahn, Tae-Sung ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 126~126
Koreasat orbit determination algorithm based on the conventional least-square estimation theory is extended to include stationkeeping maneuver
estimation for the estimation accuracy improvement and thruster performance analysis. Orbit determination results based on Koreasat F1, F2 real tracking data, show that extended time span of the tracking data resulted from
estimation, improves orbit determination results. In addition, by appling the modified algorithm to Koreasat F1 & F2, the problems arising in Koreasat orbit determination are analysed and solutions to those problems are proposed. furthermore, orbit determination results are used to analyse E/W drift induced by N/S stationkeeping maneuver.
A Study for Predicting Pilot-Induced Oscillations by Flight Simulation
Ahn, Young-Tae ; Lee, Sang-Kee ; Ko, Nak-Yong ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 137~137
A method for predicting the susceptibility of an aircraft to longitudinal pilot-induced oscillations(PIO) is introduced. This method uses the pilot transfer function model formulated for the compensatory pitch attitude command tracking tasks. Parameters of the pilot model and control system are chosen by optimization method. The tendencies of PIO were evaluated with step response of the pilot-in-the-loop simulation by varying the time delay of the pilot model. Results of simulations show that the step response is diverged by increasing the time delay of the pilot model.
Flight Simulation and Control System Design Software for Prototype Development
Ro, Kap-Seong ; Yeom, Chan-Hong ; Demyanov, Mykhaylo S. ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 144~144
Flight simulation and control system design (FS&CSD) software to be used for a prototype development is presented. This software is developed in
environment in that all inputs and outputs of complex aircraft motion and its systems are represented by simple block diagram models. The software includes typical linear models as well as a full six degree-of-freedom nonlinear model for the entire flight envelope including the motion on the ground. Using these block models with standard features and various toolboxes of
, the software can be used to design and test stability ana control augmentation system by various methodologies. An iterative numerical procedure is described, which computes initial conditions for practical cases of steady-state airplane motion. Also designed is an easy to use graphical user interface to make the software amenable to the procedures of simulation tasks as well as visualizing and analyzing the simulation results.
A Study on KOMPSAT Fault Management Design and Test
Baek, Myung-Jin ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 158~158
While the satellite is performing its mission, it is required for the satellite to have the on-board fault management autonomous function of detecting the fault and transitioning the system into the safe situation, in case that there happens an anomaly situation of jeopardizing the satellite's safety temporarily or permanently due to the malfunction of the satellite. KOMPSAT(Korea Multi-Purpose SATellite) has the function of fault management and it implies on-board computer hardware reconfiguration and satellite system reconfiguration for the hardware and software fault. Through the KOMPSAT fault management end-to-end test, the reliability of the test has been enhanced with the use of flight model hardware and software and with the setting of the test initial conditions very closely to the actual flight condition. The test has been performed successfully and the KOMPSAT fault management system performance has been verified. In this paper, KOMPSAT fault management design and its test will be discussed.
The Trend of Satellite Bus Structures Technology Development
Ro, Soo-Hyuk ; Park, Jong-Sung ; Park, Joon-Seong ; Kim, Chang-Ho ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 170~170
High-Resolution Remote Sensing Satellite with Application
Roh, Yong-Kyu ; Lee, Gue-Won ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 27, issue 8, 1999, Pages 181~181