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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 44, Issue 9 - Sep 2016
Volume 44, Issue 8 - Aug 2016
Volume 44, Issue 7 - Jul 2016
Volume 44, Issue 6 - Jun 2016
Volume 44, Issue 5 - May 2016
Volume 44, Issue 4 - Apr 2016
Volume 44, Issue 3 - Mar 2016
Volume 44, Issue 2 - Feb 2016
Volume 44, Issue 1 - Jan 2016
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Aeroacoustics Analysis and Noise Reduction of Dual Type Combined Fan using Lattice-Boltzmann Method
Kim, Wootaek ; Ryu, Minhyung ; Kim, Jinwook ; Ho, Sunghwan ; Cho, Leesang ; Cho, Jinsoo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 44, issue 5, 2016, Pages 381~390
DOI : 10.5139/JKSAS.2016.44.5.381
In this study, aeroacoustic characteristics of combined fan are investigated and noise was reduced by applying Serrated Trailing Edge which is known as the method to reduce fan noises. Unsteady CFD (Computational Fluid Dynamics) analysis was carried out using Lattice Boltzmann Method(LBM) to figure out the combined fan`s aeroacoustics and experimental results was used to verify simulation results. Results show that different BPFs are generated at the each inner fan and outer fan on the different frequency while Blade Passing Frequency(BPF) of general fans is constant on the entire frequency range. Boundary vortex and vortex shedding are suppressed or dispersed by applying the Serrated Trailing Edge to the inner fan. Furthermore, broadband noise and fan`s torque are reduced.
Comparison of Aerodynamic Loads for Horizontal Axis Wind Turbine (I): with and without Turbulent Inflow
Kim, Jin ; Kang, Seung-Hee ; Ryu, Ki-Wahn ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 44, issue 5, 2016, Pages 391~398
DOI : 10.5139/JKSAS.2016.44.5.391
This study focused on the aerodynamic loads of the horizontal axis wind turbine blade due to the normal turbulence inflow condition. Normal turbulence model (NTM) includes the variations of wind speed and direction, and it is characterized by turbulence intensity and standard deviation of flow fluctuation. IEC61400-1 recommends the fatigue analysis for the NTM and the normal wind profile (NWP) conditions. The aerodynamic loads are obtained at the blade hub and the low speed drive shaft for MW class horizontal axis wind turbine which is designed by using aerodynamically optimized procedure. The 6-components of aerodynamic loads are investigated between numerical results and load components analysis. From the calculated results the maximum amplitudes of oscillated thrust and torque for LSS with turbulent inflow condition are about 5~8 times larger than those with no turbulent inflow condition. It turns out that the aerodynamic load analysis with normal turbulence model is essential for structural design of the wind turbine blade.
Comparison of Aerodynamic Loads for Horizontal Axis Wind Turbine (II): with and without Vertical Wind Shear Effect
Kim, Jin ; Kang, Seung-Hee ; Ryu, Ki-Wahn ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 44, issue 5, 2016, Pages 399~406
DOI : 10.5139/JKSAS.2016.44.5.399
The large scale wind turbine blades usually experience periodic change of inflow speed due to blade rotation inside the ground shear flow region. Because of the vertical wind shear, the inflow velocity in the boundary layer region is maximum at uppermost position and minimum at lowermost position. These spatial distribution of wind speeds can lead to the periodic oscillation of the 6-component loads at hub and low speed shaft of the wind turbine rotor. In this study we compare the aerodynamic loads between two inflow conditions, i.e, uniform flow (no vertical wind shear effect) and normal wind profile. From the computed results all of the relative errors for oscillating amplitudes increased due to the ground shear flow effect. Especially bending moment and thrust at hub, and bending moments at LSS increased enormously. It turns out that the aerodynamic analysis including the ground shear flow effect must be considered for fatigue analysis.
An Adaptive Guided Filter for Performance Improvement of Aviation Image Fusion
Kim, Sun Young ; Kang, Chang Ho ; Park, Chan Gook ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 44, issue 5, 2016, Pages 407~415
DOI : 10.5139/JKSAS.2016.44.5.407
In this paper, an aviation image fusion method is proposed for creating an informative fused image through gray scale images within noise. The proposed method is based on an adaptive guided filter which adjusts regulation parameter of the filter based on peak signal noise ratio (PSNR) in order to behave as an edge-preserving filtering property. Simulation results demonstrate that the proposed method preserves the edge information of the input image and reduces the noise effect while maintaining designed PSNR.
Preliminary Performance Analysis of Satellite Formation Flying Testbed by Attitude Tracking Experiment
Eun, Youngho ; Park, Chandeok ; Park, Sang-Young ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 44, issue 5, 2016, Pages 416~422
DOI : 10.5139/JKSAS.2016.44.5.416
This paper presents preliminary performance analysis of a satellite formation flying testbed, which is under development by Astrodynamics and Control Laboratory, Department of Astronomy, Yonsei University. A model reference adaptive controller (MRAC) with a first-order reference model is chosen to enhance the response of reaction wheel system which is subject to uncertainties caused by unmodelled dynamics and measurement noise. In addition, an on-line parameter estimation (OPE) technique based on the least square is combined to eliminate the effect of angular measurement noise by estimating the moment of inertia. Both numerical simulations and hardware experiments with MRAC support the effectiveness and applicability of the adaptive control scheme, which maintains the tracking error below
for the entire time span. However, the high frequency control input generated in hardware experiment strongly suggests design modifications to reduce the effect of deadzone.
Development and Validation of Manned and Unmanned Aircraft Simulation Engine for Integrated Operation in NAS
Kim, Dong-Hyun ; Kim, Jun-Hyung ; Yoon, Sug-Joon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 44, issue 5, 2016, Pages 423~430
DOI : 10.5139/JKSAS.2016.44.5.423
Recently, manned and unmanned aerial vehicles are faced with problems such as collision detection and avoidance, link-loss for integrated operations in NAS. Hence, on the basis of the performance data of EUROCONTROL`s BADA and NASA, an environment was developed to simultaneously handle simulations of integrated operations of MAVs and UAVs along with ATC/ATM simulations, and dynamic modeling was then carried out. To validate the developed model, simulations were performed on a 6-DOF model by its segments and the results were compared to the RMSE results.
Design and manufacture of a self-powered quadcopter
Lee, Yun Seong ; Kim, Yoonsoo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 44, issue 5, 2016, Pages 431~438
DOI : 10.5139/JKSAS.2016.44.5.431
In this paper, a self-powered quadcopter is designed and manufactured. The quadcopter gains extra power via two types of generators which utilize the principle of electromagnetic induction. One of the types is to make use of a commercial BLDC motor which rotates together with a propeller and thus acts as a generator. The other type is to make use of a coil-wound ring around a propeller which generates electricity when small magnets embedded in a uniquely designed frame rotate together with the propeller. The proposed generators are expected to be of practical use when they are located under the propellers of a quadcopter.
Dynamic Characteristics of Helicopter Bearingless Main Rotor
Yun, Chul Yong ; Song, Keun Woong ; Kim, Deog-Kwan ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 44, issue 5, 2016, Pages 439~446
DOI : 10.5139/JKSAS.2016.44.5.439
The characteristics of bearingless main rotor of helicopter are investigated through non-rotating tests and rotating tests. The stiffness and natural frequencies of rotor blades, flexbeam, and torque tube which are core components of baearingless rotor are measured to obtain input material properties for rotor analysis. The functional test on ground for assembly of one hub with damper, snubber, and no blade is carried out to check interfaces between components, kinematics of components, and pitch motion ranges under applied loads including centrifugal load. The 4-bladed bearingless rotor with 5.82m of rotor radius is tested on the whirl tower with rotation plane of 9.65m height. The thrust and power are measured to obtain hover performance and the frequencies and dampings of the rotor are obtained by excitation of cyclic pitch by hydraulic actuators.
Tracking and Orbit Determination of International Space Station using Radar
Yu, Ki-Young ; Chung, Dae-Won ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 44, issue 5, 2016, Pages 447~454
DOI : 10.5139/JKSAS.2016.44.5.447
Increase of space debris makes low earth orbit(LEO) environment more complex day by day and space situation Awareness(SSA) is becoming more important. As an essential part of SSA, space object surveillance and tracking is studied by many countries including America and Europe. And radar system forms the backbone of an space surveillance and tracking. Currently, Korea operates many LEO satellites like KOMPSAT but does not have dedicated radar systems which provide collision surveillance between satellite and space debris. Korea Aerospace Research Institute(KARI) NARO space center operates launch-vehicle tracking radar system in GOHEUNG and JEJU, respectively. In this paper, we describe developing operation concept to track International Space Station(ISS) using NARO radar and results of tracking. Then, we describe ISS orbit determination using radar tracking data. Lastly, orbit determination result is compares with TLE for analyzing effectiveness of orbit determination.
Numerical Investigation of Temperature Uniformity and Estimation Accuracy for MEMS-based Black Body System
Chae, Bong-Geon ; Kim, Tae-Gyu ; Lee, Jong-Kwang ; Kang, Suk-joo ; Oh, Hyun-Ung ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 44, issue 5, 2016, Pages 455~462
DOI : 10.5139/JKSAS.2016.44.5.455
Output Characteristics of the spaceborn image sensor such as infrared(IR) sensor are varied according to time elapses and sensor repetition on/off operation. As a result, the quality of IR sensor image is decreased. Therefore, spaceborne image sensor require a periodic calibration using a black body system by correcting a non-uniformity of the sensor. In this paper, we proposed a MEMS-based black body system that can implement the high temperature uniformity at various standard temperatures ranging from low to high temperature and easily estimate the representative surface temperature. In addition, it has advantages lightweight, low-power and high accuracy. The feasibility of the proposed MEMS-based black body system was verified through the thermal analysis.