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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 30, Issue 8 - Dec 2002
Volume 30, Issue 7 - Oct 2002
Volume 30, Issue 6 - Sep 2002
Volume 30, Issue 5 - Aug 2002
Volume 30, Issue 4 - Jun 2002
Volume 30, Issue 3 - May 2002
Volume 30, Issue 2 - Apr 2002
Volume 30, Issue 1 - Feb 2002
Selecting the target year
Design and Analysis for the Propeller of MAVs in Low Reynolds Number Flows
Lee, Ki-Hak ; Kim, Kyu-Hong ; Lee, Kyung-Tae ; Ahn, Jon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 1~8
DOI : 10.5139/JKSAS.2002.30.5.001
The performance of MAV(Micro Air Vehicles) propellers is highly affected by the aerodynamic characteristics of a 2-D blade airfoil shapes. XFOIL is used to predict the lift and drag coefficients in low Reynolds Number flows. ARA-D 6%, which shows a good performance in low Reynolds Number regions, is selected as a blade airfoil. The 3-D propeller blade shape is optimized with the minimum energy loss condition, and the distribution of aerodynamic coefficients of ARA-D 6% is calculated. The designed optimal blade is compared with the Black Widow's propeller blade shape in the same conditions. The results indicate that the designed propeller installed in MAV can provide a good performance.
Higher order zig-zag plate theory for coupled thermo-electric-mechanical smart structures
Oh, Jin-Ho ; Cho, Maeng-Hyo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 9~14
DOI : 10.5139/JKSAS.2002.30.5.009
A higher order zig-zag plate theory is developed to accurately predict fully coupled mechanical, thermal, and electric behaviors. Both the in-plane displacement and temperature fields through the thickness are constructed by superimposing linear zig-zag field to the smooth globally cubic varying field. Smooth parabolic distribution through the thickness is assumed in the transverse deflection in order to consider transverse normal deformation. Linear zig-zag form is adopted in the electric field. The layer-dependent degrees of freedom of displacement and temperature fields are expressed in tern-is of reference primary degrees of freedom by applying interface continuity conditions as well as bounding surface conditions of transverse shear stresses and transverse heat flux. The numerical examples of coupled and uncoupled analysis demonstrate the accuracy and efficiency of the present theory. The present theory is suitable for the predictions of fully coupled behaviors of thick smart composite plate under mechanical, thermal, and electric loadings combined.
A Study on a large-scale materials simulation using a PC networked cluster
Choi, Deok-Kee ; Ryu, Han-Kyu ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 15~23
DOI : 10.5139/JKSAS.2002.30.5.015
For molecular dynamics requires high-performance computers or supercomputers to handle huge amount of computation, it is not until recent days that the application of molecular dynamics to materials fracture simulations draw some attention from many researchers. With the recent advent of high-performance computers, computation intensive methods become more tractable than ever. However, carrying out materials simulation on high-performance computers costs too much in general. In this study, a PC cluster consisting of multiple commodity PCs is established and computer simulations of materials with cracks are carried out on it via molecular dynamics technique. The effect of the number of nodes, speedup factors, and communication time between nodes are measured to verify the performance of the PC cluster. Upon using the PC cluster, materials fracture simulations with more than 50,000 molecules are carried out successfully.
An Experimental Study on the Effects of Tabs and Small Proturbances Inside Nozzle on Supersonic Jet Flowfield
Jin, Won-Jin ; Cho, Chang-Kwon ; Lee, Yeol ; Yoon, Woong-Sup ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 24~31
DOI : 10.5139/JKSAS.2002.30.5.024
The effects of vortex generators, in the form of small delta-shaped tabs or thin tapes at an axi-symmetric supersonic nozzle exit, on the characteristics of supersonic jet flowfields are investigated by Schlieren images and Pitot-tube measurements. Small tabs as small as 1 % of the nozzle exit area can introduce streamwise vortices and produce a significant effect on the jet flowfield downstream of the nozzle. The effect is stronger for the cases of under-expanded jet than over- and perfect-expanded cases, introducing a larger flow entrainment. The effects of the angle of tabs with respect to the flow direction are also investigated, and for over-expanded jet cases, it is found that the tabs bended toward upstream can weaken the interaction strength and remove the Mach disc in the jet flowfield. Introduction of small proturbances inside the nozzle surface by attachment of thin tapes is also found to change the pressure distribution in the circumferential direction of the flowfield. Its effect is also found to be dependent on the jet expansion ratio.
Numerical Analysis of Rarefied Hypersonic Flows Using Generalized Hydrodynamic Models for Diatomic Gases
Myong, Rho-Shin ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 32~40
DOI : 10.5139/JKSAS.2002.30.5.032
The study of nonlinear gas transport in rarefied condition or associated with the microscale length of the geometry has emerged as an interesting topic in recent years. Along with the DSMC method, several fluid dynamic models that come under the general category of the moment method or the Chapman-Enskog method have been used for this type of problem. In the present study, on the basis of Eu's generalized hydrodynamics, computational models for diatomic gases are developed. The rotational nonequilibrium effect is included by introducing excess normal stress associated with the bulk viscosity of the gas. The new models are applied to study the one-dimensional shock structure and the multi-dimensional rarefied hypersonic flow about a blunt body. The results indicate that the bulk viscosity plays a considerable role in fundamental flow problems such as the shock structure and shear flow. An excellent agreement with experiment is observed for the inverse shock density thickness.
Guidance Laws for Aircraft Automatic Landing
Min, Byoung-Mun ; No, Tae-Soo ; Song, Ki-Jung ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 41~47
DOI : 10.5139/JKSAS.2002.30.5.041
In this paper, a guidance law applicable to aircraft automatic landing is proposed and its performance is compared with the conventional ILS-type landing approach. The concept of miss distance, which is commonly used in the missile guidance laws, and Lyapunov stability are effectively combined to obtain the landing guidance law. The new landing guidance law is integrated into the existing controller and is applied to the landing approach and flare phases of landing procedure. Numerical simulation results show that the new landing guidance law is a viable alternative to the conventional strategies that directly control the longitudinal deviation or altitude.
Internet-based Repair for Aircraft Composites
Chu, Won-Sik ; Ahn, Sung-Hoon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 48~55
DOI : 10.5139/JKSAS.2002.30.5.048
An Internet-based software called the Repair Advisory Service (RAS) was developed to assist aircraft composite repair. The RAS takes advantage of the web user interface and provides estimation of the failure loads of repaired composite laminates and Structural Repair Manual (SRM) with search capability. In this paper, a failure model of lap repair is discussed as an example of the modules in the RAS. The model takes into account anisotropy of each ply in the laminate and in the repair ply, and non-elastic behavior of the interlayer between the laminate and the repair patch. Failure loads calculated by the model were compared with test data, and a good agreement was found between the results of the model and the test.
Subsonic Flutter Experiment and Analysis of Flat Plate Wing
Bae, Jae-Sung ; Kim, Jong-Yun ; Yang, Seung-Man ; Lee, In ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 56~61
DOI : 10.5139/JKSAS.2002.30.5.056
Experimental flutter test for a flat plate wing is performed and the flutter analysis methods are verified by comparing with the experimental results. Wing model and experimental equipment are established in the subsonic wind-tunnel. From the response of the wing, the flutter speed is estimated by using the system identification technique. MSC/NASTRAN, V-g method and root-locus method are used for the flutter analysis of the wing. The computed flutter speed is compared with the estimated one from the experiment, and they show good agreement. Wing model in the present study can be used as a benchmark model for the flutter analysis.
Prediction of Gas Turbine Engine Steady Performance from Transient Performance Test
Yang, In-Young ; Jun, Yong-Min ; Kim, Chun-Taek ; Nam, Sam-Sik ; Yang, Soo-Seok ; Lee, Dae-Sung ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 62~70
DOI : 10.5139/JKSAS.2002.30.5.062
Methodology of predicting steady performance of gas turbine engine from transient test data was explored to develop an economic performance test technique. Discrepancy of transient performance from steady performance was categorized as dynamic, thermal and aerodynamic transient effects. Each effect was mathematically modeled and quantified to provide correction factors for calculating steady performance. Engine performance tests were conducted at Altitude Engine Test Facility of KARI. The influence of engine inlet/outlet condition change on engine performance was corrected firstly, and then steady performance was predicted from the correction factors. The result was compared with steady performance test data. This correction method showed an acceptable level of precision, 3.68% difference of fuel flow.
A Study on Self-Similarity in Turbulent Hydrogen Jet Flames with Coaxial Air
Kim, Mun-Ki ; Kim, Seung-Han ; Yoon, Young-Bin ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 71~78
DOI : 10.5139/JKSAS.2002.30.5.071
Experiments have been performed using two-color PIV in hydrogen non-premixed flames with various conditions of coaxial air, which was classified into three cases with/without reaction. Mean velocity, turbulence intensity and Reynolds stress were analyzed using flow fields from PIV measurement First, the similarity of pure jet had a good agreement with previous results of other researchers. It was found that the decay of centerline velocity was proportional to
in coaxial air conditions. By normalizing axial distance with effective jet diameter defined by effective density, the data of centerline velocity collapsed a single line. And the radial profiles of mean velocity showed that they didn't become self-similar because the curves differed from each other as coaxial air velocity increased at fixed fuel velocity. Also, turbulence intensity became self-similar further downstream than mean velocity.
A Numerical Study on Sensitivity of Acoustic Response to Pressure Oscillations in Liquid Rocket Engine
Sohn, Chae-Hoon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 79~87
DOI : 10.5139/JKSAS.2002.30.5.079
Acoustic responses to pressure oscillations in axisymmetric combustion chamber are numerically investigated to examine the qualitative trend of acoustic instability in liquid rocket engine. Chamber operating condition and excitation frequency of oscillating pressure are selected as exciting parameters of acoustic instability. Artificial perturbation is simulated by total-pressure oscillation with sine wave at chamber inlet. Many approximations and simplifications are introduced without losing the essence of acoustic pressure response. First, steady-state solution for each operating condition is obtained and next, transient analysis is conducted. Depending on operating condition and excitation frequency, the distinct response characteristics are brought. Weak-strength flames and high-frequency excitation tend to cause sensitive acoustic pressure response leading to unstable pressure field. These results are analyzed based on the correlation with acoustic pressure responses from the previous works adopting laminar flamelet model.
The Role of Nano-particles on the Material Properties of Epoxy/Fe
Park, Joo-Hyuk ; Kim, Jung-Yub ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 88~93
DOI : 10.5139/JKSAS.2002.30.5.088
The objective of this study is to obtain fundamental understandings involving the manufacturing process of nano-composite via resin transfer molding and explore the role of nano sized
particles in the epoxy/
nano-composites. To achieve this goal, following investigations have been conducted: Define the optimum dispersion technique of nano-particles, identify the effect of the nano-particles to the resin viscosity, characterize the key mechanical properties versus particle loading amounts, and explore the usefulness and quality improvement in nano-composites. These efforts will be useful for designers to quantify application payoffs and define a technology development roadmap for manufacturing nano-composites, and will help an engineering design and manufacturing nano-composites more efficiently by providing the design methodology.
Development of Lightweight Piezo-composite Curved Actuator
Park, Ki-Hoon ; Yoon, Kwang-Joon ; Park, Hoon-Cheol ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 94~100
DOI : 10.5139/JKSAS.2002.30.5.094
This paper is concerned with the development, and performance test of LIPCA (Lightweight Piezo-composite Curved Actuator) that is lighter than other conventional piezo-composite type actuators. LIPCA is composed of top fiber composite layers with a high modulus and low CTE (Coefficient of Thermal Expansion), a middle PZT cermaic wafer, and base layers with a high modulus and high CTE. The performance of each actuator was evaluated using an actuator test system consisting of an actuator supporting jig, a high voltage actuating power supplier, and a non-contact laser measuring system. The simply supported condition actuator was excited by the power supplier with 1.0Hz cycle and up to
. The displacement at the center point of actuator was measured with non-contact laser displacement measuring system, It has been shown that the LIPCA-C2 can 34% decrease in mass and 13% increase in displacement compared to THUNDER.
Numerical Analysis and Control of Open Cavity Flow
Chang, Kyung-Sik ; Park, Seung-O ; Choi, Hun-Ki ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 101~108
DOI : 10.5139/JKSAS.2002.30.5.101
A numerical simulation of an incompressible cavity flow is conducted. Two dimensional Navier-Stokes equations are integrated using staggered grid and a finite volume method with C-QUICK scheme for spatial derivatives and fully implicit scheme for the time derivatives. SIMPLE-C algorithm is employed to solve the pressure field. Computational results show that the third eddy is generated in the shear layer mode but not in the steady mode. This signifies that the third eddy plays an important role in cavity flow stability. As a means to control the flow, jet blowing is applied to a position below the cavity upstream edge. Effects of flow control parameters on the stability such as the frequency, the phase, and the velocity magnitude are reported.
Visualization Study of High-Incidence Vortical Flow over the LEX/Delta Wing Configuration with Sideslip
Sohn, Myong-Hwan ; Lee, Ki-Young ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 109~117
DOI : 10.5139/JKSAS.2002.30.5.109
An off-surface flow visualization experiments have been performed to investigate the flow field over a delta wing with the leading edge extension(LEX). The model is a flat wing with
sweepback angle. The free stream velocity is 6.2 m/s, which corresponds to Reynolds number of
based on the wing root chord. The angle of attack and sideslip angle range from
, respectively. The visualization technique of using the micro water-droplet and the laser beam sheet enabled to observe the vortical flow structures, which can not be obtained by 5-hole probe measurements. With sideslip angle, the interaction and breakdown of the LEX and wing vortices was promoted in the windward side, whereas, it was suppressed in the leeward side.
Small Turbojet Engine Test and Uncertainty Analysis
Jun, Yong-Min ; Yang, In-Young ; Nam, Sam-Sik ; Kim, Chun-Taek ; Yang, Soo-Seok ; Lee, Dae-Sung ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 118~126
DOI : 10.5139/JKSAS.2002.30.5.118
The Altitude Engine Test Facility(AETF) was built at the Korea Aerospace Research Institute and has been being operated for the gas turbine engines in the class of 3,000 lbf thrust. To enhance the confidence level of AETF to the international level, a series of studies and facility modification have been conducted to improve the measurement uncertainty and reliability. In this paper, some part of the facility evaluation tests performed with a single spool turbojet engine are introduced. Tests were performed simulating the flight conditions as steady state, sea level for various flight speeds (i.e., Mn=0.3, 0.5, 0.7, 0.9). The obtained test results are compared with the predicted values of the engine DECK. The measurement uncertainties of airflow, net thrust, fuel flow and SFC showed 0.791~0.914%, 0.851~1.706%, 1.372~7.348% and 1.642~5.205%, respectively. Thus, from this research, the improvement methods of uncertainties on AETF has been confirmed.
Full Scale Durability Test of Basic Trainer
Joo, Young-Sik ; Kim, Min-Sung ; Park, Byung-Hoon ; Shul, Chang-Won ; Kim, Ho-Yeon ; Jung, Jae-Kwon ; Jeong, Byeong-Woo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 127~133
DOI : 10.5139/JKSAS.2002.30.5.127
The general requirements to achieve the structural integrity of the airframe are described in the military specification, MIL-STD-1530A. One of these requirements is the durability and damage tolerance of the airframe, which should be shown through the analysis and test based on the related specifications. This paper introduces the full scale durability test to evaluate the structural safety and durability of the basic trainer, KT-1. The test was performed according to the procedure in the military specification. The flight by flight load spectrum was developed by KT-1 fatigue load criteria and used for the durability test. The durability test had been performed for 4 service lives and was completed successfully. Therefore, it was shown that KT-1 airframe satisfied the durability requirements.
GPS Receiver for Satellite Launcher
Kim, Cheon-Joong ; Choi, Hyung-Don ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 30, issue 5, 2002, Pages 134~142
DOI : 10.5139/JKSAS.2002.30.5.134