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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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Numerical Study of Separated Nozzle Flows for Various Pressure Ratios
Kim, Hui-Kyung ; Park, Seung-O ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 1~9
DOI : 10.5139/JKSAS.2002.30.8.001
Axisymmetric separated flows in a converging-diverging conical nozzle are investigated through numerical simulations for various pressure ratios. We employ AUSM scheme for spatial derivatives and Pulliam's 2nd order subiteration time stepping scheme for implicit time integration. Numerical results indicate that the separated flow structures are very complex when compared to the simple quasi-one dimensional flow. Depending on the pressure ratio, the flow within the nozzle is either separated or non-separated. Various separated flow patterns with distinctive features are illustrated and discussed in detail.
Dynamic Stall Control Using Aerodynamic Sensitivity Analysis
Ahn, Tai-Sul ; Kim, Hyoung-Jin ; Kim, Chong-Am ; Rho, Oh-Hyun ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 10~20
DOI : 10.5139/JKSAS.2002.30.8.010
The present paper investigates methods to control dynamic stall using an optimal approach. An unsteady aerodynamic sensitivity analysis code is developed by a direct differentiation method from a two-dimensional unsteady compressible Navier-Stokes solver including a two-equation turbulence model. Dynamic stall control is conducted by minimizing an objective function defined at an instant instead of integrating for a period of time. Unsteady sensitivity derivatives of the objective function are calculated by the sensitivity code, and optimization is carried out using a linear line search method at every physical time step. Numerous examples of dynamic stall control using control parameters such as nose radius, maximum thickness of airfoil, or suction show satisfactory results.
Study on the Passive Shock/Boundary Layer Interaction Control in Transonic Moist Air Flow
Baek, Seung-Cheol ; Kwon, Soon-Bum ; Kim, Heuy-Dong ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 21~29
DOI : 10.5139/JKSAS.2002.30.8.021
In the present study, a passive control method, using a porous wall and cavity system, is applied to the shock wave/boundary layer interactions in transonic moist air flow. The two-dimensional, unsteady, compressible, Navier-Stokes equations, which are fully coupled with a droplet growth equation, are solved by the third-order MUSCL type TVD finite difference scheme. Baldwin-Lomax model is employed to close the governing equations. In order to investigate the effectiveness of the present control method, the total pressure loss of the flow and the time-dependent behaviour of shock motions are analyzed in detail. The computed results show that the present passive control method considerably reduces the total pressure losses due to the shock wave/boundary layer interaction in transonic moist air flow and suppresses the unsteady shock wave motions over the airfoil as well. It is also found that the location of the porous ventilation significantly affects the control effectiveness.
The correction of support interference effect of belly sting
Kim, Nam-Gyun ; Ahn, Seung-Ki ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 30~36
DOI : 10.5139/JKSAS.2002.30.8.030
Wind tunnel model has some difference in shape compared to the real flight vehicle because of model support system for testing. The support system can make some differences in the measured forces and moments to the flight test data. There are several correction methods involved such as cavity pressure correction and model support interference. Internal balance and belly sting support were used for this wind tunnel test and three types of model support correction methods, variable sting thickness method, dummy sting method, and wire support method, were compared. Variable sting thickness method is well matched with wire support method, which is known for almost interference free.
Prediction of Aeroelastic Displacement Under Close BVI Using Unstructured Dynamic Meshes
Jo, Kyu-Won ; Oh, Woo-Sup ; Kwon, Oh-Joon ; Lee, In ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 37~45
DOI : 10.5139/JKSAS.2002.30.8.037
A two-dimensional unsteady, inviscid flow solver has been developed for the simulation of airfoil-vortex interactions on unstructured dynamically adapted meshes. The Euler solver is based on a second-order accurate implicit time integration using a point Gauss-Seidel relaxation scheme and a dual time-step subiteration. A vertex-centered, finite-volume discretization is used in conjunction with the Roe's flux-difference splitting. An unsteady solution-adaptive dynamic mesh scheme is used by adding and deleting mesh points to take account of both spatial and temporal variations of the flow field. The effect of vortex interaction on the aeroelastic displacement of an airfoil attached to the idealized two degree-of-freedom spring system is investigated.
Transonic/Supersonic Nonlinear Aeroelastic Analysis of a Complete Aircraft Using High Speed Parallel Processing Technique
Kim, Dong-Hyun ; Kwon, Hyuk-Jun ; Lee, In ; Kwon, Oh-Joon ; Paek, Seung-Kil ; Hyun, Yong-Hee ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 46~55
DOI : 10.5139/JKSAS.2002.30.8.046
A nonlinear aeroelastic analysis system in transonic and supersonic flows has been developed using high speed parallel processing technique on the network based PC-clustered machines. This paper includes the coupling of advanced numerical techniques such as computational structural dynamics (CSD), finite element method (FEM) and computational fluid dynamics (CFD). The unsteady Euler solver on dynamic unstructured meshes is employed and coupled with computational aeroelastic solvers. Thus it can give very accurate engineering data in the structural and aeroelastic design of flight vehicles. To show the great potential of useful application, transonic and supersonic flutter analyses have been conducted for a complete aircraft model under developing in Korea.
Compressive Behavior for Smart Skin of Sandwich Structure
Kim, Young-Sung ; Kim, Yong-Bum ; Park, Hoon-Cheol ; Yoon, Kwang-Joon ; Lee, Jeo-Hwa ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 56~64
DOI : 10.5139/JKSAS.2002.30.8.056
In this work, a smart skin of multi-layer structure is designed and manufactured. Through the compression test, the characteristic of smart skin behavior was examined. We have predicted stress of each layer and the first failed layer of the smart skin structure by using MSC/NASTRAN. The finite element model was verified by comparing measured data from the compression test and result from the geometrically linear/non-linear analysis. The finite element model was used for obtaining design data from the parametric study. It was confirmed that shear moduli of honeycomb core affect the buckling load of smart skin where shear deformation was considerable.
A Study on the Brazed Joint of Duplex Stainless Steel with Ni Base Insert Metal
Rhee, Byong-Ho ; Ma, Chang-Ik ; Kim, Dae-Up ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 65~70
DOI : 10.5139/JKSAS.2002.30.8.065
The brazing of duplex stainless steels which is an essential process for rocket engine manufacturing has been investigated on bonding phenomena and shear strength. The UNS32550 was used for base metal, and the MBF-50 was used for insert metal. Brazing was carried out under the various conditions (brazing temperature : 1473K, 1498K, holding time : 0, 0.3, 0.9, 1.8 ks). There were various phases in the joint because of reaction between liquid insert metal and base metal, In the early stage, BN is formed in the bonded interlayer and base metal near the bonded layer. Cr nitride is formed in the bonded interlayer. The amount of BN and Cr nitride decrease with the increase of holding time. Superior shear strength of 550MPa is obtained by restraining the formation of nitride.
Extension of the LQR to Accomodate Actuator Saturation Bounds for Flexible Space Structures
Lee, Sang-Chul ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 71~77
DOI : 10.5139/JKSAS.2002.30.8.071
We consider the simultaneous slewing and vibration suppression control problem of an idealized structural model which has a rigid hub with two cantilevered flexible appendages and finite tip masses. The finite clement method(FEM) is used to obtain linear finite dimensional equations of motion for the model. In the linear quadratic regulator(LQR) problem, a simple method is introduced to provide a physically meaningful performance index for space structure models. This method gives us a mathematically minor but physically important modification of the usual energy type performance index. A numerical procedure to solve a time-variant LQR problem with inequality control constraints is presented using the method of particular solutions.
The Block Decorrelation Method for Integer Ambiguity Resolution of GPS Carrier Phase Measurements
Tran, Binh Quoc ; Lim, Sam-Sung ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 78~86
DOI : 10.5139/JKSAS.2002.30.8.078
The GPS carrier phase measurements include integer ambiguities and the decorrelation process on the variance-covariance matrix is necessary to resolve these ambiguities efficiently. In this paper, we introduce a new method for the ambiguity de-correlation. This method divides the variance-covariance matrix into 4 smaller blocks and decorrelates them separately. The decorrelation of each block is processed recursively so that the result of the previous step is not affected by the next step. A couple of numerical examples chosen in random show that this method is better than or comparable to other decorrelation methods, however, the speed of this is relatively faster because the computations are performed on small blocks of the variance-covariance matrix.
A Study on the Station Relocation of the Koreasat
Lee, Sang-Cherl ; Park, Bong-Kyu ; Kim, Bang-Yeop ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 87~93
DOI : 10.5139/JKSAS.2002.30.8.087
In general, station relocation for a geostationary orbit satellite is formulated as a request for moving the spacecraft from its present longitude to the target longitude within a given time interval. The station relocation maneuver is composed of drift orbit insertion maneuver and target orbit insertion maneuver. During station relocation, the satellite orbit is continually influenced by the non-spherical geo-potential. When we plan a maneuver, if we do not consider the influence, the satellite may not be relocate to desired longitude successfully. To solve this problem, we applied the linearised orbit transfer equation to acquire maneuver time and delta-V. Nonlinear simulation for the station relocation of multiple satellites is performed in order to verify the distance between two satellites.
Reliability Analysis of the Communications & Broadcasting Satellite Transponder and its Optimal Design
Kim, Young-Suk ; Chang, Young-Keun ; Jeong, Chul-Oh ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 94~102
DOI : 10.5139/JKSAS.2002.30.8.094
Since it would be almost impossible to recover and/or repair the satellite in space once it has been launched, a detailed analysis and design, manufacturing using the high quality workmanship, and qualification and acceptance tests in space-simulation environments are necessary for all satellite components prior to launch. Even though these efforts arc made, the failure can still occur. Therefore, redundancy should be considered in the satellite design for continuous operations in preparation for part or equipment failure. In this paper, the reliability analysis of the transponder, which is a payload of Communications & Broadcasting Satellite being developed by ETRI, was performed and compared for various design cases with different redundancies to find the optimal design. The optimal design has been finalized by investigating how the redundant components are composed from the viewpoint of technical performance measures, such as reliability, cost, schedule, and mass.
Life Prediction Analysis of Power Generation Turbine Blades Through Creep Analysis
Park, Jung-Sun ; Lee, Soo-Yong ; Kim, Jong-Un ; Lee, An-Sung ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 103~111
DOI : 10.5139/JKSAS.2002.30.8.103
Steady-state creep analysis of power generation turbine blade is carried out considering thermal loads and centrifugal forces. Creep strains and stresses of the turbine blade are calculated for 3-D finite clement model of the turbine blade. From the numerical results, creep life of the turbine blade is predicted. The results of creep analysis during about 200 hours indicate that creep strains of the turbine blade do not reach the rupture strain of GTD111. Creep stresses of the turbine blade are relaxed as time increases. Maximum creep strain occurs at the tip section of the airfoil pressure surface. The maximum creep strain of the turbine blade is expected close to the rupture strain after 50,000 hours approximately. The turbine blade may not have creep damage for the starting procedure of the turbine.
Numerical Analysis on 3-dimensional Heat transfer of Heating Surface with Periodically Arrayed Injectors
Cho, Won-Kook ; Kim, Young-Mog ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 112~119
DOI : 10.5139/JKSAS.2002.30.8.112
Three dimensional numerical heat transfer analysis was carried out against periodically arranged fuel injectors of the liquid rocket engine. A finite volume method based on SIMPLE algorithm was adapted which gave a good agreement with the published results of the heat transfer problem of a backward facing step. The Nusselt number and pressure drop increased as the distance between the injector elements decreased. When the Reynolds number increased, the Nusselt number increased but nondimensionalized pressure drop decreased slightly.
Hot Fire Tests of the KSR-III Sub.(I) Engines
Kim, Y.H. ; Kim, Y.W. ; Moon, I.Y. ; Ko, Y.S. ; Lee, S.Y. ; Ryu, C.S. ; Seol, W.S. ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 120~125
DOI : 10.5139/JKSAS.2002.30.8.120
In the preceding tests using the KSR-III Sub.(I) engines, it was observed that the heat resistant capability of the engines was not enough for the mission. So Sub.(I) Mod. engines were designed and tested. The Sub.(I) Mod. engines have three major design parameters - the arrangement of main injectors, the impinging angle of main injectors and thermal barrier coating. More than twenty experiments were carried on to evaluate engine performance and heat resistance capability with respect to design parameters. In this study, the test results are introduced. Analysing the result of Sub.(I) engine tests, it is found that decreasing the impinging angle, adopting the H-type arrangement(rather than radial type arrangement) and adopting the thermal barrier coating can increase heat resistance capacity substantially. Also, engine performance evaluation is conducted using specific impulse and characteristic velocity parameter. The results show that the performance variation is small(about 5%) and the performance is better in the case of radial arrangement. It is suspected that these phenomena are caused by the change of flame structure atomization mixing characteristic of sprays and the distortion of recirculation zone. Also from the low frequency instability point of view, it is observed that reducing the impinging angle and adopting the H type arrangement can increase the instability characteristics.
Micro-Vibration Measurement, Analysis and Attenuation Techniques of Reaction Wheel Assembly in Satellite
Oh, Shi-Hwan ; Rhee, Seung-Wu ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 126~132
DOI : 10.5139/JKSAS.2002.30.8.126
Jitter induced from several payloads on-board satellites degrade the performance of pointing accuracy and attenuate the resolving power of highly-precise camera image such as KOMPSAT II. In this paper, we introduce a micro-vibration measurement technique, analysis of dynamic characteristics, and modeling method for a reaction wheel assembly which is one of the major sources of jitter in satellites and an effective vibration reduction techniques are considered. Based on these techniques, vibration measurement and passive control were performed with an micro-vibration generator which was designed to have similar dynamic performances with an actual reaction wheel assembly above 50Hz.
Development of Integrated Navigation Computer for On/Off Line Processing
Jin, Yong ; Park, Chan-Gook ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 133~140
DOI : 10.5139/JKSAS.2002.30.8.133
In this paper, the structure of integrated navigation computer for experiment is proposed. It is designed for considering the real time processing and data storage capacity. It will be used in missile, aircraft, submarine system and experimental vehicle. The I/O device supports IMU, GPS, odometer, altimeter, depth sensor, inclinometer etc. And the main storage device uses the tape device. That can improve the system stability. Therefore it can be used in a high dynamic or shock environment. The embedded linux is used as an Operating System. For the real time capability, sensor data processing and algorithm processing units are seperated. The time synchronization is referenced by IMU data.
Estimation of Thruster Efficiency for Koreasat I, II under APEMAC Operation
Park, Young-Woong ; Park, Bong-Kyu ; Nam, Moon-Gyung ; Bang, Hyo-Choong ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 141~147
DOI : 10.5139/JKSAS.2002.30.8.141
Estimation of thrusters efficiency is a very important process at the end of lifetime of a satellite. This paper introduces a technique to estimate the efficiency change of thrusters considering bubble effect for Koreasat I. During APEMAC(Automatic Pitch Error/ Momentum Adjust Control), the change in thruster efficiency is estimated to compare the attitude telemetry data of the Koreasat I with the results of the control logic using Simulink. The outcome of this study is expected to contribute to improving the operational load at the end of generic communication satellite mission.
A Study on Solar Panel Installation Angles for Stratospheric Platform Airship Power Systems
Kim, Hyoung-Jin ; Lee, Chang-Ho ; Yang, Soo-Seok ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 148~155
DOI : 10.5139/JKSAS.2002.30.8.148
A study on the installation angle of solar panels is conducted as a conceptual study on solar-RFC(regenerative fuel cell) system for stratospheric airships. The airship heads for the west in winter days and the east in summer days according to wind directions. Considering this, it is found that when the solar panel is installed with the center angle of 30 degree the energy output of solar panels is maximized on winter solstice and satisfies the required energy of summer days as well. Although with the optimized solar panel installation angle, efficiency of the regenerative power system needs be improved to 47% to provide required energy of a 170m-long airship. And the required amount of efficiency improvement decreases as the airship size increases.
Introduction to Mission Requirement and Technical Trend of Rotary-wing Unmanned Aerial Vehicle System
Lee, Kyung-Tae ; Oh, Chol-Jun ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 156~163
DOI : 10.5139/JKSAS.2002.30.8.156
Satellite Launching Sites of Foreign Countries
Jung, Hae-Seung ; Lee, Soo-Jin ; Lee, Jae-Deuk ; Cho, Gwang-Rae ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 8, 2002, Pages 164~172
DOI : 10.5139/JKSAS.2002.30.8.164