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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
Application of CFD in The Analysis of Aerodynamic Characteristics for Aircraft Propellers
Cho, Kyuchul ; Kim, Hyojin ; Park, Il-Ju ; Jang, Sungbok ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 11, 2012, Pages 917~926
DOI : 10.5139/JKSAS.2012.40.11.917
The analysis of aerodynamic characteristics for aircraft propellers is studied to develop high efficiency composite propellers. It is to verify the accuracy and reliability of predicting the efficiency characteristics of aircraft propellers by applying nonlinear numerical analysis. The numerical simulation method incorporated the CFD code, which is based on RANS (Reynolds Averaged Navier-Stocks) equation. The study includes a comparative analysis between the numerical simulation results and the wind tunnel test results of the full-scale aircraft propeller. The comparison shows that thrust and power coefficients of the propeller calculated by nonlinear numerical analysis are higher than those based on the results generated from the wind tunnel test. The efficiency of the propeller calculated by numerical analysis matches closely to the efficiency based on the wind tunnel test results. The verification results are analyzed, then, will be used in optimizing the design and manufacture of the subject aircraft propeller studied.
Experimental Study of Thrust Vectoring of Supersonic Jet Utilizing Co-flowing Coanda Effects
Yoon, Sang-Hun ; Jun, Dong-Hyun ; Heo, Jun-Young ; Sung, Hong-Gye ; Lee, Yeol ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 11, 2012, Pages 927~933
DOI : 10.5139/JKSAS.2012.40.11.927
The characteristics of two-dimensional supersonic coanda flow was experimentally investigated. For various ratios of slot height to coanda wall`s radius of curvature, surface roughnesses, and jet stagnation pressures, the characteristics of the supersonic coanda flow such as shock structures and hysteresis were observed by flow visualization. It was found that the characteristics of hysteresis of the coanda jet was related to the surface roughness of the coanda wall. The study was further extended for application of the tangentially injected coanda jet to control co-flowing highly compressible main jet direction. It was noticed that the stagnation pressure of the main jet as well as the ratio of the slot height to coanda wall`s radius of curvature wall was an influencing factor in the performance of the fluidic thrust vectoring method.
A Study on the Performance Analysis of the PAO-AIR Heat Exchangers in an Aircraft
Park, Dong-Myung ; Joung, Yong-In ; Moon, Woo-Yong ; Park, Sung-Sun ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 11, 2012, Pages 934~939
DOI : 10.5139/JKSAS.2012.40.11.934
In this study, the performance validation of a PAO-AIR heat exchanger developed for the ECS(Environmental Control System) of a UAV(Unmanned Aerial Vehicle) has been carried out. The performance goals of a PAO-AIR heat exchanger were established by the system schematic analysis. And a heat exchanger to be met the ECS performance was developed by a detailed design and a precision manufacture. Using the developed heat exchanger, the experiment about pressure loss and effectiveness, overall heat transfer coefficient to prove the developed PAO-AIR heat exchanger performance in various conditions as well as a design point of heat exchanger was performed and the experimental results were analyzed. As the experimental results, the performance and characteristic of a PAO-AIR heat exchanger developed for the ECS of a UAV were analyzed and the development suitability was proved.
A Study on Optimum Takeoff Time of the Hybrid Electric Powered Systems for a Middle Size UAV
Lee, Bohwa ; Park, Poomin ; Kim, Keunbae ; Cha, Bongjun ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 11, 2012, Pages 940~947
DOI : 10.5139/JKSAS.2012.40.11.940
The target system is a middle size UAV, which is a low-speed long-endurance UAV with a weight of 18 kg and wingspan of 6.4 m. Three electric power sources, i.e. solar cells, a fuel cell, and a battery, are considered. The optimal takeoff time is determined to maximize the endurance because the generated solar cell`s energy is heavily dependent on it. Each power source is modeled in Matlab/Simulink, and the component models are verified with the component test data. The component models are integrated into a power system which is used for power simulations. When takeoff time is at 6 pm and 2 am, it can supply the power during 37.5 hrs and 27.6 hrs, respectively. In addition, the thermostat control simulation for fuel cell demonstrates that it yields more power supply and efficient power distribution.
Prediction of Longitudinal and Directional Stability Derivatives for the SDM using Forced Harmonic Oscillation
Lee, Hyungro ; Lee, Seungsoo ; Joh, Chang-Yeol ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 11, 2012, Pages 948~956
DOI : 10.5139/JKSAS.2012.40.11.948
This paper presents the computations of the longitudinal and directional stability derivatives for the SDM(Standard Dynamic Model). The static and dynamic derivatives are evaluated at once using forced harmonic oscillations in the pitch and yaw directions. For the numerical simulations, a 3-D Euler solver that uses a dual time stepping method for unsteady time accurate simulations is applied. This work investigates the variation of the derivatives in terms of the Mach number and the several motion parameters. Good agreement of the pitch and yaw stability derivatives with previously published numerical results and experimental results are observed.
An efficient method for fluid/structure interaction analysis considering nonlinear structural behavior
Kim, Euiyoung ; Chang, Seongmin ; Lee, Dongho ; Cho, Maenghyo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 11, 2012, Pages 957~962
DOI : 10.5139/JKSAS.2012.40.11.957
Fluid/structure interaction (FSI) analysis is necessary to predict the response of a system in which aerodynamic pressure causes deformation of the structure, and vice versa. In dealing with a nonlinear behavior of the structure, however, a simple iterative algorithm of aerodynamic analysis with structural analysis yields no accurate results since aerodynamic pressure need to be changed in accordance with the deformation of structures. In this study, we explore an efficient and accurate method for integrating FSI analysis into structural nonlinear systems. During the course of nonlinear structural analysis, loading conditions are periodically updated by aerodynamic analysis. The accuracy and efficiency of the method is demonstrated with a high-aspect-ratio flexible wing of Global Hawk.
Design Optimization of a Wing Structure under Multi Load Spectra using PSO algorithm
Park, Kook Jin ; Park, Yong Jin ; Cho, Jin Yeon ; Park, Chan Yik ; Kim, Seung Jo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 11, 2012, Pages 963~971
DOI : 10.5139/JKSAS.2012.40.11.963
In this paper, development of optimal design tools for wing structure is described including multi load spectra condition and fatigue analysis. Two dimensional CFD result are used for calculating aerodynamic force. Design variables are composed of a number of rib and spar, positions, and thickness of each structural member. The mission profile for fatigue analysis is composed based upon the results of CFD analysis, the flight-by-flight spectra method, the excessive curves for gust loads. Minor`s rule was used to deal with multi-load condition. Stress analysis and fatigue analysis are performed to calculate objective functions. Particle Swarm Optimization(PSO) algorithm was used to apply to problems which have dozens of design variables.
Parallelization of Multifrontal Solution Method for Shared Memory Architecture
Kim, Min Ki ; Kim, Jeong Ho ; Park, Chan Yik ; Kim, Seung Jo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 11, 2012, Pages 972~978
DOI : 10.5139/JKSAS.2012.40.11.972
This paper discusses the parallelization of multifrontal solution method, widely used for finite element structural analyses, for a shared memory architecture. Multifrontal method is easier than other linear solution methods because the solution procedure implies that unknowns can be eliminated simultaneously. Two innovative ideas are introduced to achieve optimal solver performance on a shared memory computer. Those are pairing two frontal matrices and splitting the frontal matrix in order to reduce the temporal memory space required by independent computing tasks. Performance comparisons between original algorithm and proposed one prove that proposed method is more computationally efficient on current multicore machines.
Trajectory Generation, Guidance, and Navigation for Terrain Following of Unmanned Combat Aerial Vehicles
Oh, Gyeong-Taek ; Seo, Joong-Bo ; Kim, Hyoung-Seok ; Kim, Youdan ; Kim, Byungsoo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 11, 2012, Pages 979~987
DOI : 10.5139/JKSAS.2012.40.11.979
This paper implements and integrates algorithms for terrain following of UCAVs (Unmanned Combat Aerial Vehicles): trajectory generation, guidance, and navigation. Terrain following is very important for UCAVs because they perform very dangerous missions such as Suppression of Enemy Air Defences while the terrain following can improve the survivability of UCAVs against from the air defence systems of the enemy. To deal with the GPS jamming, terrain referenced navigation based on nonlinear filter is chosen. For the trajectory generation, Voronoi diagram is adopted to generate horizontal plane path to avoid the air defense system. Cubic spline method is used to generate vertical plane path to prevent collisions with ground while flying sufficiently close to surface. Follow-the-Carrot and pure pursuit tracking methods, which are look-ahead point based guidance algorithms, are applied for the guidance. Numerical simulation is performed to verify the performance of the integrated terrain following algorithm.
Distributed Task Assignment Algorithm for SEAD Mission of Heterogeneous UAVs Based on CBBA Algorithm
Lee, Chang-Hun ; Moon, Gun-Hee ; Yoo, Dong-Wan ; Tahk, Min-Jea ; Lee, In-Seok ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 11, 2012, Pages 988~996
DOI : 10.5139/JKSAS.2012.40.11.988
This paper presents a distributed task assignment algorithm for the suppression of enemy air defense (SEAD) mission of heterogeneous UAVs, based on the consensus-based bundle algorithm (CBBA). SEAD mission can be modeled as a task assignment problem of multiple UAVs performing multiple air defense targets, and UAVs performing SEAD mission consist of the weasel for destruction of enemy`s air defense system and the striker for the battle damage assessment (BDA) or other tasks. In this paper, a distributed task assignment algorithm considering path-planning in presence of terrain obstacle is developed for heterogeneous UAVs, and then it is applied to SEAD mission. Through numerical simulations the performance and the applicability of the proposed method are tested.
Compensation of Magnetometer in the Navigation System for Unmanned Helicopter using an Electric Motor
Lee, Gilho ; Jo, Sungbeom ; Kim, Jungsung ; Choi, Keeyoung ; Kee, Changdon ; Song, Yongkyu ; Koo, Wheonjoon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 11, 2012, Pages 997~1003
DOI : 10.5139/JKSAS.2012.40.11.997
GNSS and ARS are the most common sensors in low-end UAVs. However, these sensors are vulnerable to built-in errors and cannot measure the body heading independently. The GNSS/INS cannot fully compensate the IMU errors in initial alignment process and rectilinear flights. For an unmanned helicopter, a magnetometer can be more useful than any other sensors to obtain heading information. However, the electric motor which drives small helicopter UAV keeps the magnetometer from reading the pure magnetotelluric vector. This paper shows the effects of electric motor on the magnetometer readings, and presents a method to compensate the effects. The results are verified with flight test data. The simulation and experimental results in this paper proves that aiding GNSS/INS with magnetometer increases observability and improves accuracy.
The use of Interfacial Graphene to Carbon nanotube Point emitter for Field Emission Electric Propulsion
Lee, Jeong Seok ; Kang, Tae June ; Kim, Dae Weon ; Kim, Yong Hyup ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 11, 2012, Pages 1004~1009
DOI : 10.5139/JKSAS.2012.40.11.1004
Carbon nanotube are nanostructure with extraordinary field emission properties like high current density, low driving voltage and long time stability, because of their high electrical conductivity, high aspect ratio for geometrical field enhancement and superior thermal stability. But, there is some problem to mate metal and carbon nanotube, we have resolved this problem by using interfacial graphene. This approach takes advantage of superior electric and thermal conductivity between metal and carbon nanotube and shows superior performance compared to the existing field emitters. This result shows that such a carbon nanotube emitter in a stage where it can be used for Field Emission Electric Propulsion (FEEP).
Development of Thin-Film Thermo-Electrochemical Cell for Harvesting Waste Thermal Energy
Im, Hyeongwook ; Kang, Tae June ; Kim, Dae Weon ; Kim, Yong Hyup ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 40, issue 11, 2012, Pages 1010~1015
DOI : 10.5139/JKSAS.2012.40.11.1010
In this study, a thin-film thermo-electrochemical cell that directly converts waste thermal energy into electrical energy was fabricated. Electrical conductivity of conducting carbon fiber, which was used as flexible electrode, was increased through coating of carbon nanotube, and resistance of the CNT-coated fiber electrode was not changed even after bending test with various curvatures. Maximum output power of the thermocell was increased quadratically with the temperature difference, and showed a value of about 2.5 mW/kg at temperature difference of
. As a result of discharge test for 12 hours, it is confirmed that the cell can operates continuously. And thin-film thermocell wrapped around a pipe with hot liquid flowing within was demonstrated. Internal resistance of the cell was decreased with various curvature of heat pipe, and maximum output power was increased by 30 %. Therefore, the cell can be applied to various heat source.