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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 41, Issue 12 - Dec 2013
Volume 41, Issue 11 - Nov 2013
Volume 41, Issue 10 - Oct 2013
Volume 41, Issue 9 - Sep 2013
Volume 41, Issue 8 - Aug 2013
Volume 41, Issue 7 - Jul 2013
Volume 41, Issue 6 - Jun 2013
Volume 41, Issue 5 - May 2013
Volume 41, Issue 4 - Apr 2013
Volume 41, Issue 3 - Mar 2013
Volume 41, Issue 2 - Feb 2013
Volume 41, Issue 1 - Jan 2013
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Numerical analysis of the vortex induced vibration of the 2-D cylinder using dynamic deforming mesh
Lee, Namhun ; Baek, Jiyoung ; Lee, Seungsoo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 1, 2013, Pages 1~9
DOI : 10.5139/JKSAS.2013.41.1.1
In this paper, numerical simulations are performed on the lock-in phenomena of vortex induced vibration(VIV) of a two dimensional cylinder. A deforming grid as well as a rigidly moving grid are used to simulate the movement of the cylinder. The grid deformation is accomplished by the linear spring analogy. Converged solutions, which are obtained by controling the grid size and the non-dimensional time step, are used for comparison and validation of the analysis results. Moreover, the efficiency and the accuracy of the coupling methods for fluid-structure interaction are examined.
Effective Perceived Noise Level Prediction for a Propeller driven UAV by using Wind Tunnel Test Data
Ryi, Jae-Ha ; Rhee, Wook ; Choi, Jong-Soo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 1, 2013, Pages 10~16
DOI : 10.5139/JKSAS.2013.41.1.10
This paper discussed a procedure for noise certification of Aircraft and predicting the full scale over-flight noise of propeller from acoustic wind tunnel measurement of small scale propeller. Noise Certification Procedures is established from International Civil Aviation Organization(ICAO). The data manipulations are then discussed in extrapolation to simulation flight distance and flight simulation. One of the most important point of flight simulation is adjustments for differences between wind tunnel test conditions and flight test conditions. To simulated the noise level estimation procedure for noise data post-process, simulate procedures from data of the wind tunnel noise measurement and the flight noise measurement by using a 7kg degree UAV. This study confirmed an effectively noise estimation procedures by wind tunnel noise test and flight noise test.
Micro-mechanical Failure Prediction and Verification for Fiber Reinforced Composite Materials by Multi-scale Modeling Method
Kim, Myung-Jun ; Park, Sung-Ho ; Park, Jung-Sun ; Lee, Woo-Il ; Kim, Min-Sung ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 1, 2013, Pages 17~24
DOI : 10.5139/JKSAS.2013.41.1.17
In this paper, a micro-mechanical failure prediction program is developed based on SIFT (Strain Invariant Failure Theory) by using the multi-scale modeling method for fiber-reinforced composite materials. And the failure analysis are performed for open-hole composite laminate specimen in order to verify the developed program. First of all, the critical strain invariants are obtained through the tensile tests for three types of specimens. Also, the matrices of strain amplification factors are determined through the finite element analysis for micro-mechanical model, RVE (Representative Volume Element). Finally, the microscopic failure analysis is performed for the open-hole composite laminate specimen model by applying a failure load obtained from tensile test, and the predicted failure indices are evaluated for verification of the developed program.
Performance Testing of an Integrated Hybrid Actuator
Xuan, Zhefeng ; Jin, Tailie ; Goo, Nam Seo ; Bae, Byung-Woon ; Kim, Tae-Heun ; Ko, Han Seo ; Yoon, Ki-Won ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 1, 2013, Pages 25~30
DOI : 10.5139/JKSAS.2013.41.1.25
The piezoelectric-based hydraulic actuator is a hybrid device consisting of a hydraulic pump driven by piezoelectric stacks that is coupled to a conventional hydraulic cylinder via a set of fast-acting valves. Nowadays, such hybrid actuators are being researched and developed actively in many developed countries by requirement of high performance and compact flight system. In this research, operation principle and performance testing of the hybrid actuator were introduced. Output velocities have been measured in both loaded case and not loaded case and the blocking force also has been measured in external loaded case. The maximum velocity of the actuator is 53.3 mm/s, blocking force is 240.7 N and corresponding power output is 3.2 W.
A Study on Longitudinal Flight Dynamics of a QTW UAV
Jung, Ji In ; Hong, Sung Tae ; Kim, Seungkeun ; Suk, Jinyoung ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 1, 2013, Pages 31~39
DOI : 10.5139/JKSAS.2013.41.1.31
A Quad Tilt Wing UAV is a new concept hybrid UAV having the advantages of both fixed-wing and rotary-wing aircraft. This paper presents longitudinal flight dynamic characteristics of a Quad Tilt Wing UAV. The designed Quad Tilt Wing UAV is a configuration of a tandem wing type aircraft with an actuating motor and propeller mounted at each wing. Momentum theory is used to calculate the thrust, and nonlinear modeling is performed considering lift and drag generated by slip stream effect of propellers. Also, Force and moment variation at each tilting angle is considered. Static trim on longitudinal axis is analyzed via numerical simulation. Componentwise force contribution was analyzed at each trim mode. Dynamic characteristics were evaluated through eigenvalue analysis for a linear model at each flight mode. It is verified that longitudinal dynamic characteristics are changing from unstable to stable state by continuous transition of dominant poles.
Vortex sheddings and Pressure Oscillations in Hybrid Rocket Combustion
Park, Kyungsoo ; Shin, Kyung-Hoon ; Lee, Changjin ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 1, 2013, Pages 40~47
DOI : 10.5139/JKSAS.2013.41.1.40
The similarity in internal flow of solid and hybrid rocket suggests that hybrid rocket combustion can be susceptible to instability due to vortex sheddings and their interaction. This study focuses on the evolution of interaction of vortex generated in pre-chamber with other types of vortex in the combustor and the change of combustion characteristics. Baseline and other results tested with disks show that there are five different frequency bands appeared in spectral domain. These include a frequency with thermal lag of solid fuel, vortex shedding due to obstacles such as forward, backward facing step and wall vortices near surface. The comparison of frequency behavior in the cases with disk 1 and 3 reveals that vortex shedding generated in pre-chamber can interact with other types of vortex shedding at a certain condition. The frequency of Helmholtz mode is one of candidates resulting to a resonance when it was excited by other types of oscillation even if this mode was not discernable in baseline test. This selective mechanism of resonance may explain the reason why non-linear combustion instability occurs in hybrid rocket combustion.
Optimal Basis Function Selection for Polynomial Response Surface Model Using Genetic Algorithm
Kim, Sang-Jin ; You, Heung-Cheol ; Bae, Seung-Ho ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 1, 2013, Pages 48~53
DOI : 10.5139/JKSAS.2013.41.1.48
Polynomial response surface model has been widely used as approximation model which replace physical or numerical experiments in various engineering fields. Generally, low-order model is used to reduce experimental points required to construct the response surfaces, but this approach has limit to represent the highly non-linear phenomena. In this paper, we developed the method to expand modeling capabilities of polynomial response surfaces by increasing order of polynomial and selecting optimum polynomial basis functions. Genetic algorithm is used to choose optimal polynomial basis functions. Developed method was applied to analytic functions with 1 or 2 variables and wind tunnel test data modeling. The results show that this method is applicable to building response surface models for highly non-linear phenomena.
Ground Altitude Computation Algorithm using Laser Altimeter and GPS for UAV Automatic Take-off and Landing
Cho, Sangook ; Choi, Keeyoung ; Kim, Sung-Su ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 1, 2013, Pages 54~60
DOI : 10.5139/JKSAS.2013.41.1.54
This paper presents a ground altitude determination algorithm using a laser altimeter and GPS for automatic take-off and landing of UAV. The characteristics of the laser altimeter was analyzed in ground tests and a low-pass filter was designed to reduce the effect of signal interruption due to reflectivity problem. The paper shows that a single sensor cannot measure ground altitude appropriately in terms of reliability and accuracy. To complement shortcomings of the laser altimeter, the linear Kalman filter was designed using DGPS vertical speed. Designed filter was validated and tuned through the steps of simulation, ground test and flight test. It was confirmed that the accuracy for automatic landing is achievable.
S/W Development of Flying Qualities Evaluation in Virtual Flight Test using MATLAB GUI
Cho, Seung-Gyu ; Rhee, Ihn-Seok ; Kim, Byoung-Soo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 1, 2013, Pages 61~69
DOI : 10.5139/JKSAS.2013.41.1.61
In an evaluation process of aircraft flying qualities, a clear and concise application interface is important since an evaluation process requires numerous repeated evaluation. This flight evaluation program have implemented efficient flight evaluation user interface along with changed trim condition interface and composed of comprehensive evaluation interface have mounted all automated FQ evaluation modules that was selected to be compose of 14 items in respect of an unmanned fixed-wing aircraft. Accordingly when it is necessary to design the flight control system as well as to develop a FQ considered aircraft, this S/W can be utilized as a tool that is a useful test evaluation S/W with scalability and enable to reduce the time and the cost of verification and evaluation process.
Analysis of GPS Signal Environment for GBAS siting in Gimpo International Airport
Jeong, Myeong-Sook ; Choi, Chul Hee ; Ko, Wan-Jin ; Ko, Youri ; Bae, Joongwon ; Jun, Hyang-Sig ; Kim, Dong-Min ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 1, 2013, Pages 70~78
DOI : 10.5139/JKSAS.2013.41.1.70
Before GBAS ground systems is installed at the airport, the site survey is needed to determine the suitability of proposed GBAS candidate sites depending on the siting requirements. Therefore, analysis of GPS signal reception environment, one of the site survey steps, is required. In this paper, the number of visible satellites, GPS signal strength, multipath error, radio frequency interference and predicted availability were analyzed using the GPS data of Gimpo International Airport measured by PortaSAT equipments and the analysis results were represented.
TID and SEL Testing on PWM-IC Controller of DC/DC Power Buck Converter
Lho, Young Hwan ; Hwang, Eui Sung ; Jeong, Jae-Seong ; Han, Changwoon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 1, 2013, Pages 79~84
DOI : 10.5139/JKSAS.2013.41.1.79
DC/DC switching power converters are commonly used to generate a regulated DC output voltage with high efficiency. The DC/DC converter is composed of a PWM-IC (pulse width modulation-integrated circuit) controller, a MOSFET (metal-oxide semiconductor field effect transistor), inductor, capacitor, etc. It is shown that the variation of threshold voltage and the offset voltage in the electrical characteristics of PWM-IC increase by radiation effects in TID (Total Ionizing Dose) testing at the low energy
, and 4 heavy ions applied for SEL (Single Event Latch-up) make the PWM pulse unstable. Also, the output waveform for the given input in the DC/DC converter is observed by the simulation program with integrated circuit emphasis (SPICE). TID testing on PWM-IC is accomplished up to the total dose of 30 krad, and the cross section(
) versus LET(
) in the PWM operation is studied at SEL testing after implementation of the controller board.