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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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Accurate and Robust Computations of Gas-Liquid Two-Phase Flows Part 1: Development of Shock-Stable Two-Phase Schemes
Ihm, Seung-Won ; Kim, Chong-Am ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 1, 2009, Pages 1~16
DOI : 10.5139/JKSAS.2009.37.1.001
In this paper, we introduce two-phase versions of RoeM and AUSMPW+ schemes. Both schemes are originally developed for the gas dynamic problems, and have shown superior accuracy, efficiency and robustness. A new shock discontinuity sensing term is derived from the mixture equation of state, which is commonly used in the RoeM and AUSMPW+ schemes for the stable numerical flux calculation. The developed two-phase versions of the schemes are applied to several liquid-gas, large property discrepancy two-phase test problems, including several shock stability test problems. The results show that both schemes maintain the merits exhibited in gas dynamic problems even in two-phase flows.
Accurate and Robust Computations of Gas-Liquid Two-Phase Flows Part 2: Preconditioned Two-Phase Schemes for All Speeds
Ihm, Seung-Won ; Kim, Chong-Am ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 1, 2009, Pages 17~27
DOI : 10.5139/JKSAS.2009.37.1.017
Two-phase RoeM and AUSMPW+ schemes are preconditioned for the simulation of all Mach number flows, which are generally of interest for many gas-liquid two-phase application problems, because of large speed of sound in liquid region and low speed of sound in mixture or gas region. Conventional characteristic based schemes lose their accuracy or robustness in low Mach number flows, because their numerical dissipation terms are scaled by speed of sound, which is too large compared with local velocity magnitude in a low Mach region. All speed versions of RoeM and AUSMPW+ reflect the eigenvalues of the preconditioned governing system, which have the same order of magnitude even in low Mach number region. From the asymptotic analysis, it is observed that the discretized system by the developed schemes is consistent with the continuum system in the incompressible limit. The numerical results show the accurate and robust behavior of the proposed shcemes for all speed two-phase flows.
A Study on Coordinated Attitude Flying for Sequential Spacecraft Tracking
Park, Young-Woong ; Bang, Hyo-Choong ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 1, 2009, Pages 28~35
DOI : 10.5139/JKSAS.2009.37.1.028
This paper derives the equation of coordinated attitude formulation taking into account the orbital dynamics of a target vehicle and the attitude of a tracking satellite in geostationary orbit. The coordinated attitude is always to communicate with the ground station during the target tracking. Because the tracking satellite could perform high angle maneuver, MRP parameters having no singular point are used. Also for the sequential tracking of several target vehicles, the equation automatically making a coordinated attitude is suggested. Coordinated attitude flying and sequential tracking are confirmed through simulations. In short, this paper shows that a satellite could track a target vehicle and communicate with ground station simultaneously using the derived equation of coordinated attitude even though without a accuracy sensor.
Averaging TRIAD Algorithm for Attitude Determination
Kim, Dong-Hoon ; Lee, Henzeh ; Oh, Hwa-Suk ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 1, 2009, Pages 36~41
DOI : 10.5139/JKSAS.2009.37.1.036
In general, accurate attitude information is essential to perform the mission. Two algorithms are well-known to determine the attitude through two or more vector observations. One is deterministic method such as TRIAD algorithm, the other is optimal method such as QUEST algorithm. This Paper suggests the idea to improve performance of the TRIAD algorithm and to determine the attitude by combination of different sensors. First, we change the attitude matrix to Euler angle instead of using orthogonalization method and also use covariance in place of variance, then apply an unbiased minimum variance formula for more accurate solutions. We also suggest the methodology to determine the attitude when more than two measurements are given. The performance of the Averaging TRIAD algorithm upon the combination of different sensors is analyzed by numerical simulation in terms of standard deviation and probability.
Trajectory Optimization for Nonlinear Tracking Control in Stratospheric Airship Platform
Lee, Sang-Jong ; Bang, Hyo-Choong ; Chang, Jae-Won ; Seong, Kie-Jeong ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 1, 2009, Pages 42~54
DOI : 10.5139/JKSAS.2009.37.1.042
Contrast to the 6-DOF nonlinear dynamic modeling of nonlinear tracking problem, 3-DOF point-mass modeling of flight mechanics is efficient and adequate for applying the trajectory optimization problem. There exist limitations to apply an optimal trajectory from point-mass modeling as a reference trajectory directly to conduct the nonlinear tracking control, In this paper, new matching trajectory optimization scheme is proposed to compensate those differences of mismatching. To verify performance of proposed method, full ascent three-dimensional flight trajectories are obtained by reflecting the real constraints of flight conditions and airship performance with and without jet stream condition. Then, they are compared with the optimal trajectories obtained from conventional method.
Thrust Profile Prediction for a Vertical Launching Missile using Similarity Law
Cho, Sung-Jin ; Kim, Eul-Gon ; Ahn, Jo-Young ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 1, 2009, Pages 55~61
DOI : 10.5139/JKSAS.2009.37.1.055
In this paper, a thrust prediction method for a developing vertical launching missile is proposed through considering a verified vertical launching missile(a baseline missile) as a model. In order to predict thrust profile of a developing vertical launching missile, both Similarity law and Pi theory are applied to the model. By comparing prediction results based on the 6-DOF program of a baseline missile with simulation results of a developing vertical launching missile, the proposed method has been indirectly verified.
Oscillation Characteristics of Turbulent Channel Flow with Wall Blowing
Na, Yang ; Lee, Chang-Jin ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 1, 2009, Pages 62~68
DOI : 10.5139/JKSAS.2009.37.1.062
The interaction between wall blowing and oxidizer flow can generate a very complicated flow characteristics in combustion chamber of hybrid rockets. LES analysis was conducted with an in-house CFD code to investigate the features of turbulent flow without chemical reactions. The numerical results reveal that the flow oscillations at a certain frequency exists on the fuel surface, which is analogous to those observed in the solid propellant combustion. However, the observation of oscillating flow at a certain frequency is only limited to a very thin layer adjacent to wall surface and the strength of the oscillation is not strong enough to induce the drastic change in temperature gradient on the surface. The visualization of fluctuating pressure components shows the periodic appearance of relatively high and low pressure regions along the axial direction. This subsequently results in the oscillation of flow at a certain fixed frequency. This implies that the resonance phenomenon would be possible if the external disturbances such as acoustic excitation could be imposed to the oscillating flow in the combustion chamber.
A Performance Study of Vent Mixer with Geometric Characteristics in Supersonic Flow
Kim, Chae-Hyoung ; Jeung, In-Seuck ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 1, 2009, Pages 69~75
DOI : 10.5139/JKSAS.2009.37.1.069
This paper studies the aerodynamic performance that the vent mixer-new conceptual supersonic mixer-showed with its geometric characteristics. The hole is 2 mm with 2 mm's distance from the wall in case 1 and with no distance in case 2. In case 3 die hole is 1 mm. Case 1 and case 2 showed the same total pressure recovery ratio, of which the case 3 was lower than that. While cases 1-3 had the same reattachment length, the shear layer was thicker in cases 1 and 2 than in case 3. Within the recirculation zone, cases 1 and 2 had lower pressure loss and higher velocity gradient difference than case 3-they enhance mixing between air and fuel. Separation bubble which is developed by the inflow into the recirculation zone has a significant effect on the total pressure recovery ratio in the combustor. Also separation bubble influences pressure distributions and recirculation flows in the recirculation zone. Therefore, inflow rate of air into the recirculation zone mainly affects the performance of vent mixer.
A Study on Pressure Control for Variable Thrust Solid Propulsion System Using Cold Gas Test Equipment
Lee, Ho-Sung ; Lee, Do-Yoon ; Park, Jong-Seung ; Kim, Joung-Keun ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 1, 2009, Pages 76~81
DOI : 10.5139/JKSAS.2009.37.1.076
A nonlinear pressure controller to actively regulate the thrust of a solid propulsion system is presented. To compensate for the parametric uncertainties with respect to the chamber pressure induced by changing nozzle throat area, Lyapunov-based parameter adaptation method has been applied. In order to verify the effectiveness of the proposed control method, the experiments were carried out using the cold gas test equipment that can simulate the operating environment of variable thrust solid propulsion system. The experiment results show that the nonlinear pressure controller has better performance than conventional P and PI controller.
Predicting Extreme-Thickness of Phase Fronts in HMX- and Hydrocarbon-based Propellants
Yoh, Jai-Ick ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 1, 2009, Pages 82~88
DOI : 10.5139/JKSAS.2009.37.1.082
The structure of steady wave system is considered which is admitted by the continuum equations for materials that undergo phase transformations with exothermic chemical reaction. With its theoretical basis in one-dimensional continuum shock structure analysis, the present approach estimates the micro-width of waves associated with phase transformation phenomena, n-heptane is selected as the hydrocarbon fuel for evaporation and condensation analysis while HMX is used for melting and freezing analysis of solid rocket propellant. The estimated thickness of evaporation - condensation front of n-heptane is on the order of
micron while the HMX melting - freezing front thickness is estimated at 1 micron.
Development of CMG Ground Simulator using Torque Sensor
Kim, Seung-Hyeon ; Lee, Seung-Mok ; Rhee, Seung-Wu ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 1, 2009, Pages 89~98
DOI : 10.5139/JKSAS.2009.37.1.089
CMG cluster which consists of four CMGs can be used to produce 3-axis torque. There are many issues that we have to investigate and validate when CMG cluster itself is developed. Thus, its ground validation and verification processes are essential. Therefore, CMG simulator which uses a torque sensor to calculate satellite attitude is proposed in this paper. Update and kalman filter are also proposed for gimbal angle problem occurred in development. The first way uses a calculated gimbal angle as a primary and a sensor angle as a scondary to reduce error. Also, the test results of specific CMG steering law as well as attitude control logic are presented as an example.
A Study on Parameters of SUAV Landing Gear Orifice
Han, Jae-Do ; Kang, Yeon-Sik ; Ahn, Oh-Sung ; Lee, Young-Sin ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 1, 2009, Pages 99~104
DOI : 10.5139/JKSAS.2009.37.1.099
In this paper, the drop characteristic of the small aircraft landing gear of SUAV has been analyzed and performed on orifice optimal design for shock absorption efficiency. The SUAV landing gear was simple oleo pneumatic type without metering pin. The landing gear was modelled by MSC ADAMS software. Drop test evaluation was conducted to confirm the analysis model. As a result of correlation between analysis and test results, it was verified that these results were coincided with very well. After confidence review of analysis model through the correlation between test and analysis results, design parametric study was performed by using confirmed analysis model. Optimal orifice size with best efficiency have been decided in this study.
Case Study of F-15 Airframe Battle Damage Repair Design and Assessment Procedure
Kim, Jong-Heon ; Joo, Young-Sik ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 1, 2009, Pages 105~112
DOI : 10.5139/JKSAS.2009.37.1.105
For the purpose of facing battle damage that a fighter is subject to in combat, following recovery procedures such as damage assessment, repair design and structural integrity evaluation are investigated. A sample study is presented on the battle damage of F-15 ECS bay, which is comprised of damage assessment and repair design based on ABDR(Aircraft Battle Damage Repair) skills and work procedure complying with AFTO(Air Force Technical Order) forms. Further, the flight safety of repaired structure is validated and the time the permanent repair should be done is estimated through the evaluation of structural integrity such as the calculation of static strength and fatigue life.