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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 40, Issue 12 - Dec 2012
Volume 40, Issue 11 - Nov 2012
Volume 40, Issue 10 - Oct 2012
Volume 40, Issue 9 - Sep 2012
Volume 40, Issue 8 - Aug 2012
Volume 40, Issue 7 - Jul 2012
Volume 40, Issue 6 - Jun 2012
Volume 40, Issue 5 - May 2012
Volume 40, Issue 4 - Apr 2012
Volume 40, Issue 3 - Mar 2012
Volume 40, Issue 2 - Feb 2012
Volume 40, Issue 1 - Jan 2012
Selecting the target year
Aerodynamic Analysis on Ski Jump Flying Postures
Son, Kap-Sik ; Ryu, Min-Hyoung ; Cho, Jin-Soo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 3, 2012, Pages 193~200
DOI : 10.5139/JKSAS.2012.40.3.193
A numerical analysis is carried out in order to obtain aerodynamic data of the ski jump. The body modelling of Korean people is used in the numerical simulation and the result is validated by comparing it with the wind tunnel experiment. A flying posture, which provides the maximum lift-to-drag ratio, is found by analyzing the aerodynamic coefficients of various flight conditions. The result of the present study can be applied to fixing the postures of Korean ski players and is expected to advance the national sports science.
Validation of Noise Prediction Theory Using Scaled Rotor Experiment for Hovering Condition
Min, An-Ki ; Ryi, Jae-Ha ; Rhee, Wook ; Choi, Jong-Soo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 3, 2012, Pages 201~208
DOI : 10.5139/JKSAS.2012.40.3.201
In this paper, a series of experiment is performed for a scaled hovering rotor in a semi-anechoic chamber and the results are compared to the noise spectra predicted by using Lowson's loading noise equation and FW-H equation. It was founded that the sound directivity pattern for both experiments and predictions are similar in their trend. Meanwhile the FW-H equation showed better agreement with experiments in the near-field noise spectra, but at the far-field the Lowson's equation performed better. The discrete noise are known to be proportional to the loading on the blades, which can be controlled by collective pitch angle of the blades. It was founded that the predicted spectra with FW-H equation come close to the measured noise spectra in low collective pitch, but in high collective pitch angles the Lowson's equation be more reliable.
The effect on fatigue life for dynamic behavior of external fuel tank horizontal fin
Kim, Geun-Won ; Shin, Ki-Su ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 3, 2012, Pages 209~214
DOI : 10.5139/JKSAS.2012.40.3.209
Recently, there were significantly increased cracks failure for external fuel tank horizontal fin of F-5 aircraft. In this paper, the dynamic behavior of horizontal fin was to quantitate by using Finite Element Method. To achieve this goal, the fatigue analysis for time and frequeucy domain has been performed by using the dynamic load spectrum of speed brake. In conclusion, it was proved that fatigue life of the horizontal fin was reduced by the influence of dynamic behavior.
Improvements of pursuit performance using episodic parameter optimization in probabilistic games
Kwak, Dong-Jun ; Kim, H.-Jin ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 3, 2012, Pages 215~221
DOI : 10.5139/JKSAS.2012.40.3.215
In this paper, we introduce an optimization method to improve pursuit performance of a pursuer in a pursuit-evasion game (PEG). Pursuers build a probability map and employ a hybrid pursuit policy which combines the merits of local-max and global-max pursuit policies to search and capture evaders as soon as possible in a 2-dimensional space. We propose an episodic parameter optimization (EPO) algorithm to learn good values for the weighting parameters of a hybrid pursuit policy. The EPO algorithm is performed while many episodes of the PEG are run repeatedly and the reward of each episode is accumulated using reinforcement learning, and the candidate weighting parameter is selected in a way that maximizes the total averaged reward by using the golden section search method. We found the best pursuit policy in various situations which are the different number of evaders and the different size of spaces and analyzed results.
Effect of Injector Cooling on Ignition of Cryogenic Spray
Kim, Do-Hun ; Lee, Jin-Hyuk ; Koo, Ja-Ye ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 3, 2012, Pages 222~229
DOI : 10.5139/JKSAS.2012.40.3.222
The cooling of a injector effects on the vapor pressure of cryogenic oxidizer spray, and it decides the phase transition point at the ignition process, when the combustion chamber pressure increases drastically. The phase transition of oxidizer spray affects the ignition characteristics, and several ignition tests with the LOx/
uni-element coaxial swirl injector was performed in the different initial temperatures of oxidizer injector, in order to investigate the effect of injector cooling on the ignition transient characteristics. At the transition point of oxidizer phase, where the combustion chamber pressure increased over the LOx vapor pressure, the temporary quenching phenomenon of the flame occurred. The lower temperature of chilled down injector and tubing tends to move up the phase transition earlier.
An Experimental Study of Test Section Velocity Calibration for Low-Speed Wind Tunnel
Oh, Se-Yoon ; Lee, Jong-Geon ; Kim, Sung-Cheol ; Kim, Sang-Ho ; Ahn, Seung-Ki ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 3, 2012, Pages 230~236
DOI : 10.5139/JKSAS.2012.40.3.230
The purpose of this research is to determine the calibration constants of the wind speed measurement systems required to calculate the wind tunnel velocity in the test section. In the present work, the aerodynamic calibration tests of the test section were conducted in the Agency for Defense Development's Low-Speed Wind Tunnel. The test speed ranged from 10 to 100 m/s with a reference pitot-static pressure probe. The validity of the calibration results was evaluated by comparing them with the previous calibration constants. The calibration results show that fair to good agreement is obtained with resonable accuracy.
Thermal Design of Cryogenic Compressor with Strategies for Keeping Performance of Micro-vibration Isolation System
Oh, Hyun-Ung ; Lee, Kyung-Joo ; Jeong, Suk-Yong ; Shin, So-Min ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 3, 2012, Pages 237~242
DOI : 10.5139/JKSAS.2012.40.3.237
Spaceborne pulse tube-type cryogenic compressors are widely used for space applications. To guarantee cooling performance of the compressor, mission life time and micor-vibration stability, suitable thermal control of compressor is required. Micro-vibration of the compressor is the one of the sources to degrade the pointing performance of observation satellite. In the present work, on-orbit thermal design of compressor in order not to degrade the performance of micro-vibration isolation system keeping the thermal control performance has been proposed and investigated through thermo-mechanical analysis.
A Study on ADS-33E with Application to the Assessment of Handling Quality for Unmanned Rotorcraft
Jeong, Hwan-Ho ; Suk, Jin-Young ; Kim, Byoung-Su ; Lee, Sang-Kee ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 3, 2012, Pages 243~250
DOI : 10.5139/JKSAS.2012.40.3.243
In this paper, a systematic consequence of evaluation method, procedure, and flight data analysis is investigated for application of ADS-33E-PRF to UAV. And it is applied to unmanned rotorcraft for evaluation. CNUHELI-020, which is developed in Chungnam National University, is used for assessment of handling quality: decoupled longitudinal and lateral/directional model were used to assess handling qualities. Evaluation flight maneuvers are categorized as hover/low-speed requirements, small-amplitude attitude change, and moderate-amplitude attitude change requirements.
Lateral and Directional SCAS Controller Design Using Multidisciplinary Optimization Program
Lee, Sang-Jong ; Lee, Jang-Ho ; Lee, Dae-Sung ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 3, 2012, Pages 251~257
DOI : 10.5139/JKSAS.2012.40.3.251
The flight controller should meet the flying qualities, stability margins, and time response requirement according to the class of a target aircraft or UAV. Classical design process of PID controller is a very time consuming process and needed trial and erros. The best way is to apply the multi-disciplinary optimization algorithm to meet the numerous constraints of controller requirements. This paper presents how multi-objective parameter optimization (CONDUIT) can be used to determine many design parameters of lateral stability and augmentation system for roll and heading controller of the small UAV. To verify the effectiveness of applying the optimization method, designed controller using optimization are compared with the baseline controller that is designed only considering the time responses.
A Study on the Performance of COMS CPS during LEOP
Chae, Jong-Won ; Han, Cho-Young ; Yu, Myoung-Jong ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 3, 2012, Pages 258~263
DOI : 10.5139/JKSAS.2012.40.3.258
In this paper the Chemical Propulsion Subsystem of COMS is briefly explained and some telemetries acquired by a series operations of CPS during the Launch and Early Operation Phase of COMS are presented. The pressure and temperature of pressurant tank telemetries are compared with the results of the developed computer program. The changes in pressure are due to the two major phases. The first one is the initialization phases of CPS composed of the venting phase to vent the helium gas in the pipe network from the downstream of the propellant tanks to the thrusters for safety, the priming phase to fill the vented pipe network with oxidizer and fuel respectively and then the pressurization phase to pressurize the ullage of propellant tank to regulated pressure. And the other is the apogee engine firings in which COMS CPS is in the orbit raising phase to use helium as a pressurant to keep the pressure of propellant tank as the liquid apogee engine get fired until COMS reached to the target orbit. This program can be applicable to prepare basis design data of the next Geostationary Satellite CPS.
TRL Impact on Development Schedule and Cost in the Aerospace Project
Hwang, Hyung-Won ; Kim, Hong-Rae ; Chang, Young-Keun ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 3, 2012, Pages 264~272
DOI : 10.5139/JKSAS.2012.40.3.264
TRL has a direct impact on development schedule and cost in the system or technology development projects. If TRL capability of development organization for specified CTEs can be accurately assessed and the impact of TRL on development schedule and cost are analyzed as detailed as possible, the risk of development schedule delay and cost increase can be minimized during the development process. This paper describes analysis results of TRL impact on development schedule and cost in the aerospace project. The development schedule and cost change are quantitatively estimated for the TRL improvement in the Unmanned Aerial Vehicle(UAV) system development program.