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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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A Two-dimensional Numerical Study of Hummingbird`s Flight Mechanisms and Flow Characteristics
Lee, Hyun-Do ; Kim, Jin-Ho ; Kim, Chong-Am ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 8, 2009, Pages 729~736
DOI : 10.5139/JKSAS.2009.37.8.729
In order to understand flow characteristics and flight mechanism of hummingbird`s flapping flight, two-dimensional numerical analysis is carried out on the flapping motion of hummingbird, Selasphorus rufus. Hummingbird`s flapping wing motion is realistically modeled from wind tunnel experimental data to perform numerical analysis. Numerical simulation shows that, as freestream velocity changes, wing trajectory is also adjusted and it substantially affects lift and thrust generation mechanism. According to this tendency, flight domain is separated as "low speed" and "high speed" regime, and each flight domain is studied for physical understanding. As a result, the lift generation during downstroke can be explained by the well-known effects, such as leading edge vortex effect, delayed stall, wake capture and so on. In addition, the lift generation during upstroke, the unique character of hummingbird, is also examined by detailed flow analysis. The thrust generation mechanism is investigated by examining the hummingbird`s wing bone structure, vortex generation pattern and the resulting pressure gradient.
Design Optimization for Loop Heat Pipe Using Tabu Search
Park, Yong-Jin ; Yun, Su-Hwan ; Ku, Yo-Cheun ; Lee, Dong-Ho ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 8, 2009, Pages 737~743
DOI : 10.5139/JKSAS.2009.37.8.737
Design optimization process and results of Loop Heat Pipe(LHP) using Tabu Search have been presented in this study. An objective of optimization is to reduce a mass of the LHP with satisfying operating temperature of a Lithium Ion battery onboard an aircraft. The battery is assumed to be used as power supply of air borne high energy laser system because of its high specific energy. The analytical models are based on a steady state mathematical model and the design optimization is performed using a Meta Model and Tabu Search. As an optimization results, the Tabu search algorithm guarantees global optimum with small computation time. Due to searching by random numbers, initial value is dominant factor to search global optimum. The optimization process could reduce the mass of the LHP which express the same performance as an published LHP.
Three Dimensional Electro-Fluid-Structural Interaction Simulation for Pumping Performance Evaluation of a Valveless Micropump
Pham, My ; Phan, Van Phuoc ; Han, Cheol-Heui ; Goo, Nam-Seo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 8, 2009, Pages 744~750
DOI : 10.5139/JKSAS.2009.37.8.744
In this study, the pumping performance of a piezoelectric valveless micropump is simulated. The micropump, which was developed in the previous work, is composed of a four-layer lightweight piezocomposite actuator, a polydimethylsiloxane (PDMS) pump chamber, and two diffusers. The piezoelectric domain, the fluid domain and the structural domain are coupled in the three-dimensional simulation. We used ANSYS for the piezoelectric and structural domains and ANSYS CFX for the fluid domain. The effects of driven frequency on the flow rate have been investigated by simulating the flow characteristics for 10 Hz and 40 Hz driven frequencies. The flow rates with respect to driven frequencies up to 300 Hz have been calculated.
Strength of Composite Single-Lap Bonded Joints with Various Manufacturing Processes for Aircraft Application
Song, Min-Gyu ; Kweon, Jin-Hwe ; Choi, Jin-Ho ; Kim, Hyo-Jin ; Song, Min-Hwan ; Shin, Sang-Joon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 8, 2009, Pages 751~758
DOI : 10.5139/JKSAS.2009.37.8.751
Failure strengths of composite single-lap adhesive joints were investigated with various parameters such as manufacturing method, overlap length and adherend thickness. A total of 335 single-lap joint specimens were tested under tension. Specimens were fabricated with 4 different manufacturing processes; cocuring without and with adhesive, secondary bonding and co-bonding. Each manufacturing process has 5 different overlap lengths and 4 different thicknesses, respectively. As expected, failure strength is higher in thicker adherend joints and lower in larger overlap length specimens. Interesting result is that the secondary bonded joints show the higher strength than the cobonded and cocured joints with adhesive, and give close or even higher strength compared with non-adhesive cocured case.
Integrated SIFT Algorithm with Feature Point Matching Filter for Relative Position Estimation
Gwak, Min-Gyu ; Sung, Sang-Kyung ; Yun, Suk-Chang ; Won, Dae-Hee ; Lee, Young-Jae ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 8, 2009, Pages 759~766
DOI : 10.5139/JKSAS.2009.37.8.759
The purpose of this paper is an image processing algorithm development as a base research achieving performance enhancement of integrated navigation system. We used the SIFT (Scale Invariant Feature Transform) algorithm for image processing, and developed feature point matching filter for rejecting mismatched points. By applying the proposed algorithm, it is obtained better result than other methods of parameter tuning and KLT based feature point tracking. For further study, integration with INS and algorithm optimization for the real-time implementation are under investigation.
Improvement of INS-GPS Integrated Navigation System using Wavelet Thresholding
Kang, Chul-Woo ; Park, Chan-Gook ; Cho, Nam-Ik ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 8, 2009, Pages 767~773
DOI : 10.5139/JKSAS.2009.37.8.767
This research have introduced wavelet signal processing technic for improving navigation signals. INS signals can be distorted with conventional pre-filtering method such as low-pass filtering by unwanted smoothing on real signals. But in this paper, wavelet thresholding method is implemented to INS signal to denoise for INS-GPS integrated system. This method reduces signal noise but not distorts the rapid varing signal. And this paper applied thresholding to INS-GPS integrated navigation system and improved navigation performance.
Numerical Study on the Unsteady Solid Rocket Propellant Combustion with Erosive Burning
Lee, Sung-Nam ; Baek, Seung-Wook ; Kim, Kyung-Moo ; Kim, Yoon-Gon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 8, 2009, Pages 774~779
DOI : 10.5139/JKSAS.2009.37.8.774
A numerical modelling was performed to predict unsteady combustion processes for the AP/HTPB/Al propellant in a solid rocket motor. Its results were compared with the experimental data. Temporal pressure development was found to match quite well with measured data. A change in propellant surface was traced using the moving grid. The propellant thickness change was also observed to confirm the erosive burning effect.
Evaluation of Static Structural Integrity for Composites Wing Structure by Acoustic Emission Technique
Jun, Joon-Tak ; Lee, Young-Shin ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 8, 2009, Pages 780~788
DOI : 10.5139/JKSAS.2009.37.8.780
AE technique was applied to the static structural test of the composite wing structure to evaluate the structural integrity and damage. During the test, strain and displacements measurement technique were used to figure out for static structural strength. AE parameter analysis and source location technique were used to evaluate the internal damage and find out damage source location. Design limit load test, the 1st and 2nd design ultimate load tests and fracture test were performed. Main AE source was detected by an sensor attached on skin near by front lug. Especially, at the 1st design ultimate test, strain and displacements results didn`t show internal damage but AE signal presented a phenomenon that the internal damage was formed. At the fracture test, AE activities were very lively, and strain and displacements results showed a tendency that the load path was changed by severe damage. The internal damage initiation load and location were accurately evaluated during the static structural test using AE technique. It is certified from this paper that AE technique is useful technique for evaluation of internal damage at static structural strength test.
Deadzone Elimination of Closed-Loop Fiber Optic Gyro using Pulse Dithering
Chong, Kyoung-Ho ; Do, Jae-Chul ; Jo, Min-Sik ; Song, Ki-Won ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 8, 2009, Pages 789~797
DOI : 10.5139/JKSAS.2009.37.8.789
Gyroscope`s deadzone is a region where can not detect the rate even though the actual rotation is applied. This paper analyzed the cause of deadzone by modeling/simulation and introduced pulse dithering method to overcome. From the testing of 3-axis fiber optic gyro system using 900m fiber, it confirmed deadzone could be effectively eliminated by combination of three factors, dither amplitude, dither frequency, and gyro loop gain.
Design and Development of Thermal Control Subsystem for an Electro-Optical Camera System
Chang, Jin-Soo ; Yang, Seung-Uk ; Jeong, Yun-Hwang ; Kim, Ee-Eul ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 8, 2009, Pages 798~804
DOI : 10.5139/JKSAS.2009.37.8.798
A high-resolution electro-optical camera system, EOS-C, is under development in Satrec Initiative. This system is the mission payload of a 400-kg Earth observation satellite. We designed this system to give improved opto-mechanical and thermal performance compared with a similar camera system to be flown on the DubaiSat-1 system. The thermal control subsystem (TCS) of the EOS-C system uses heaters to meet the opto-mechanical requirements during in-orbit operation and it uses different thermal coating materials and multi-layer insulation (MLI) blankets to minimize the heater power consumption. We performed its thermal analysis for the mission orbit using a thermal analysis model and the result shows that its TCS satisfies the design requirements.
Liquid Oxygen Test of Oxidizer Pump of a Liquid Rocket Engine
Hong, Soon-Sam ; Kim, Dae-Jin ; Kim, Jin-Sun ; Kim, Jin-Han ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 8, 2009, Pages 805~811
DOI : 10.5139/JKSAS.2009.37.8.805
An oxidizer pump of a turbopump for a 30-ton class gas generator cycle engine was tested in the medium of liquid oxygen. The turbine was driven by cold hydrogen gas in the test. The oxidizer pump was operated stably at both design and off-design conditions, satisfying the performance requirements. The pump head coefficient from the liquid oxygen test was 2~3% lower than that from the water test. The power required to run the oxidizer pump was well balanced with the power produced by the turbine.
A Study on the Force Balance of a Main Oxidizer shutoff Valve
Jeon, Jae-Hyoung ; Hong, Moon-Geun ; Kim, Hyun-Jun ; Lee, Soo-Yong ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 8, 2009, Pages 812~818
DOI : 10.5139/JKSAS.2009.37.8.812
A MOV(Main Oxidizer shutoff Valve) controls the flow rate of liquid oxygen into the rocket combustor by opening and shutting operations piloted by a pneumatic force. In order to improve the effective design for sealing parts of poppet and piston assemblies, the poppet assembly has been designed to be just contacted with the piston assembly. However, to avoid a gap at the poppet/piston contact surface and to evaluate the MOV operating performance, an analyze on the force balance during the closing motion have been performed. For the accuracy of the analysis, the friction forces and the hydraulic forces have been respectively obtained by experiments and CFD analysis. Through the analysis, some important design parameters such as the spring constant, poppet friction and orifice size in the force balance have been introduced and the required operation performance of the MOV has been proved feasible.
Analysis of the Sensory Evaluation for the Korean Space Foods Performed in ISS
Kang, Sang-Wook ; Choi, Gi-Hyuk ; Yi, So-Yeon ; Kim, Sung-Soo ; Song, Beom-Seok ; Kim, Jae-Hun ; Le, Ju-Woon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 8, 2009, Pages 819~827
DOI : 10.5139/JKSAS.2009.37.8.819
We analyzed the result of sensory evaluation for the 10 items of Korean Space Foods performed by Korean astronaut in ISS. Although there were low score items because of the individual preference difference, Most items received the high score. Also, we can confirm the possibility of the internationalization of the Korean Space Foods because international astronauts gave the high valuation. we should develop the various space foods and food package which are easy to use in space for the human exploration in the future.