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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 37, Issue 12 - Dec 2009
Volume 37, Issue 11 - Nov 2009
Volume 37, Issue 10 - Oct 2009
Volume 37, Issue 9 - Sep 2009
Volume 37, Issue 8 - Aug 2009
Volume 37, Issue 7 - Jul 2009
Volume 37, Issue 6 - Jun 2009
Volume 37, Issue 5 - May 2009
Volume 37, Issue 4 - Apr 2009
Volume 37, Issue 3 - Mar 2009
Volume 37, Issue 2 - Feb 2009
Volume 37, Issue 1 - Jan 2009
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Stability Analysis of Boundary Layers on Airfoils by using PSE
Park, Dong-Hun ; Park, Seung-O ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 11, 2009, Pages 1055~1065
DOI : 10.5139/JKSAS.2009.37.11.1055
In this study, stability analysis of boundary layers on airfoils is performed by using parabolized stability equations(PSE). Boundary layer edge conditions are obtained by compressible inviscid flow calculations. Mean velocity and temperature profiles of the laminar boundary layer are obtained by solving compressible boundary layer equations in generalized curvilinear coordinates with fourth order accuracy in the wall normal direction. Laminar mean flow profiles are used as input data for PSE to investigate growth rates of disturbances and stability characteristics. For the cases of boundary layer on NACA0012 and HSNLF(1)-0213 airfoils at Mach number 0.5, growth rates with respect to disturbance frequencies and profiles of disturbance amplitude are investigated. The effect of angle of attack on stability characteristics are examined at both upper and lower surfaces. The neutral stability curves, effect of Mach number and effect of airfoil section shapes are also analyzed.
Aerodynamic Analysis of an Arbitrary Three-Dimensional Blended Wing Body Aircraft using Panel Method
Lee, Sea-Wook ; Yang, Jin-Yeol ; Cho, Jin-Soo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 11, 2009, Pages 1066~1072
DOI : 10.5139/JKSAS.2009.37.11.1066
A panel method based on potential flow theory is developed for the steady/unsteady aerodynamic analysis of arbitrary three-dimensional Blended Wing Body aircraft. The panel method uses the piecewise constant source and doublet singularities as a solution. This potential based panel method is founded on the Dirichlet boundary condition and coupled with the time-stepping method. The present method uses the time-stepping loop to simulate the unsteady motion of the aircraft. The present method can solve the three-dimensional flow over the complex bodies with less computing time and provide various aerodynamic derivatives to secure the stability of Blended Wing Body aircraft. That will do much for practical applications such as aerodynamic designs and analysis of aircraft configurations and flight simulation.
Efficient Analysis of the Aerodynamic Characteristics of Rotor Blade Using a Reduced Order Model Based on Proper Orthogonal Decomposition Method
Jung, Sung-Ki ; Duc, NgoCong ; Yang, Young-Rok ; Cho, Tae-Hwan ; Myong, Rho-Shin ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 11, 2009, Pages 1073~1079
DOI : 10.5139/JKSAS.2009.37.11.1073
The proper orthogonal decomposition (POD) method can identify principal modes that optimally capture the energy content from large multi-dimensional data set. In this study unsteady pressure fields on the rotor blade surface of a helicopter in forward flight are expressed by a reduced order model based on the POD method. Special modes containing high energy are analyzed to investigate the aerodynamic characteristics in more efficient way. The CFD simulation of flowfields around helicopter rotor blade in hovering motion is also conducted to validate its prediction with experimental result. In the process 7 modes containing energy ratio 99% from 240 snapshots information are identified and utilized to construct a reduced order model.
Flow Control by Piezoceramic Actuator in a flat plate
Kim, Dong-Ha ; Han, Jong-Seob ; Chang, Jo-Won ; Kim, Hak-Bong ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 11, 2009, Pages 1080~1088
DOI : 10.5139/JKSAS.2009.37.11.1080
An actuator using piezoceramic material was designed in order to perform a flow control for flat plate flow. Boundary layer measurements were carried out to explore the flow disturbances by the designed actuator that was activated at low excitation frequency(15Hz). The mean velocity and fluctuation in the boundary layers were measured at
downstream from the actuator tip by a one-dimensional hot-wire probe(55P14). Results reveal that low- and high-velocity regions were observed in the vicinity of the actuator center and in the outer area of the actuator respectively, and the formation of counter-rotating streamwise vortices was predicted. The fluctuations were persistently found in the outer part of the actuator and an inflection point in the spanwise gradient of the streamwise velocity was observed. Boundary layer instability was amplified at both the actuator excitation frequency and the T-S wave frequency when the actuator was excited at low frequency.
Damage Detection in Composite Laminates using Tapping Sound
Kim, Sung-Joon ; Hong, Chang-Ho ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 11, 2009, Pages 1089~1095
DOI : 10.5139/JKSAS.2009.37.11.1089
The radiated sound pressure induced by tapping test is obtained by solving the Rayleigh integral equation. For structurally radiated sound, the sound field is directly coupled to the structural motion. Therefore the impact response should be analyzed. In this paper, the delamination model is used to analyze the impact response of delaminated composite laminates. And efficient spring-mass model has been proposed to model hammer shaped impactor. Predicted sound pressure histories are compared with test data. The influence of damage on the sound pressure and impacted force history of laminates were investigated. The results show that both radiated sound pressure and impact force history are strongly influenced by delamination on laminates. As a result, it is shown that the presented sound based tapping method was found to be reliable for detecting the damage in composite laminate.
Low-Temperature Deformation Behavior of a Stainless Steel for the Thrust Chamber Mixing Head
Lee, Keum-Oh ; Ryu, Chul-Sung ; Choi, Hwan-Seok ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 11, 2009, Pages 1096~1103
DOI : 10.5139/JKSAS.2009.37.11.1096
The predictions of the material behavior for the structural stability of thrust chamber mixing head at very-low temperatures are very important since the head is highly pressurized by the liquid oxygen with very-low temperatures and experiences impact load by the thrust of combustion chamber. The constitutive equation to express tensile deformation behavior of the material at very-low temperature to predict deformation behavior of the mixing head is formulated by composition of thermal component and athermal component based on dislocation energy barrier model suggested by Kocks. Also, increase of thermal stress components by the increase of obstacles at low temperatures is formulated to the equation similar with Ramberg-Osgood equation. The suggested model predicted well the material's behavior at the wide temperature ranges from very-low temperature to ambient temperature.
A Study on the Algorithm for Automatic Generation of Optimal Waypoint with Terrain Avoidance
Park, Jung-Jin ; Park, Sang-Hyuk ; Ryoo, Chang-Kyung ; Shin, Sung-Sik ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 11, 2009, Pages 1104~1111
DOI : 10.5139/JKSAS.2009.37.11.1104
In the low altitude, mission of the aircraft is restricted by a variety of threats such as anti-air missiles and terrain obstacles. Especially, aircraft have always a risk of ground collision near terrain. In this study, to effectively solve this problem, we developed the flight path generation algorithm that is considered the terrain avoidance. In this flight path generation algorithm, waypoints that should be passed by the UAV are selected first. The waypoints are located in the middle of the terrain obstacles. Then, physically meaningful waypoints sets are classified by Dijkstra algorithm. The optimal waypoint guidance law based on the optimal control theory is applied to produce trajectory candidates. And finally the minimum control energy trajectory is determined.
Temporary Satellite Constellation Design for the Ground Reconnaissance Mission
Kim, Hae-Dong ; Bang, Hyo-Choong ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 11, 2009, Pages 1112~1120
DOI : 10.5139/JKSAS.2009.37.11.1112
In this paper, the authors introduced a new approach to find the target orbits of each satellite in order to establish a temporary reconnaissance constellation mission to minimize the average revisit time (ART) while satisfying the constraint on fuel limit. Two distinct problems are dealt with: the first is to reconnoiter the local area with discriminating fuel constraint the second is to reconnoiter ground moving target with same fuel constraint. A preliminary effort in applying a genetic algorithm to those problems has also been demonstrated through simulation study. The results show that current ARTs of each mission are reduced by 41% and 42%, respectively, by relocating the orbit of each satellite. Naturally, the final result may depend on satellite orbits, sensor characteristics, allowable fuel cost, thruster capability, and maneuver strategies.
Offshore Wind Resource Assessment around Korean Peninsula by using QuikSCAT Satellite Data
Jang, Jea-Kyung ; Yu, Byoung-Min ; Ryu, Ki-Wahn ; Lee, Jun-Shin ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 11, 2009, Pages 1121~1130
DOI : 10.5139/JKSAS.2009.37.11.1121
In order to investigate the offshore wind resources, the measured data from the QuikSCAT satellite was analyzed from Jan 2000 to Dec 2008. QuikSCAT satellite is a specialized device for a microwave scatterometer that measures near-surface wind speed and direction under all weather and cloud conditions. Wind speed measured at 10 m above from the sea surface was extrapolated to the hub height by using the power law model. It has been found that the high wind energy prevailing in the south sea and the east sea of the Korean peninsula. From the limitation of seawater depth for piling the tower and archipelagic environment around the south sea, the west and the south-west sea are favorable to construct the large scale offshore wind farm, but it needs efficient blade considering relatively low wind speed. Wind map and monthly variation of wind speed and wind rose using wind energy density were investigated at the specified positions.
A Semi-Active Control of the Combustion Instability in a Ducted Premixed Flame
Song, Jae-Cheon ; Song, Jin-Kwan ; Hwang, Jeong-Jae ; Yoon, Young-Bin ; Lee, Jong-Guen ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 11, 2009, Pages 1131~1139
DOI : 10.5139/JKSAS.2009.37.11.1131
Combustion Instabilities are caused by a coupling between acoustic waves and unsteady heat release. They can be eliminated using passive controller such as a Helmholtz resonator. But, Helmholtz resonator is normally only effective over a narrow frequency range. In this work, Helmholtz resonator is applied for reducing the combustion oscillations and we vary the Helmholtz resonator volume using piston in oder to tune in the wide range of operating conditions. As the result, it is found that the dominant combustion oscillations can be largely reduced by optimizing the size of resonator volume. And, interesting relation for phase difference of dynamic pressure both combustor and the helmholtz resonator are presented in this paper. Also, we investigate semi-active control using Helmholtz equation and phase difference.
Flow Analyses for the Uniform Distribution of Propellants at Manifolds of a Full-scale Gas Generator
Kim, Hong-Jip ; Choi, Hwan-Seok ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 11, 2009, Pages 1140~1147
DOI : 10.5139/JKSAS.2009.37.11.1140
Flow analyses have been performed to investigate the uniformity of propellant flow through the fuel and oxidizer manifolds of a full-scaled gas generator for a pump-fed liquid rocket engines. Injectors were simulated as porous medium layers having equivalent pressure drops. The uniformity of propellants has been analyzed for 3 fuel rings and 3 injector head configurations. The mixture ratio distribution at the exit of injectors has been estimated from the mass flow rates of fuel and oxidizer. The best configuration of fuel ring and injection head was selected through these flow analyses.
Study on for Simulation of GNSS Signal Generation
Kim, Tae-Hee ; Lee, Jae-Eun ; Lee, Sang-Uk ; Kim, Jae-Hoon ; Hwang, Dong-Hwan ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 11, 2009, Pages 1148~1156
DOI : 10.5139/JKSAS.2009.37.11.1148
ETRI has developed GNSS digitized IF signal generator for providing test and evaluation environment for various software level application and navigation algorithm in Global Navigation Satellite System(GNSS). GNSS digitized IF signal generator provides two main capabilities, GPS and Galileo raw data generation and digitized IF signal generation. GNSS digitized IF signal generator consists of five main modules which are GNSS Satellite Orbit Simulation Module, Navigation Message Generation Module, Error Generation Module, GNSS IF Signal Generation Module, and Message & Signal Steering Module. We verified the signal generated by the GNSS signal generation algorithm using software receiver for generation of signal brother to real GNSS signal.
Development of STSAT-3 Battery Management System
Park, Kyung-Hwa ; Kim, Chol-Ho ; Lim, Cheol-Woo ; Kim, Jin-Kyu ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 11, 2009, Pages 1157~1163
DOI : 10.5139/JKSAS.2009.37.11.1157
This paper introduces the lithium ion battery management system for STSAT-3 satellite. The specifications of lithium ion battery unit are proposed to supply power to the satellite and the overall electrical design for lithium ion battery BMS is presented. Furthermore, the test results of battery management system are shown to verify the design.