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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 28, Issue 7 - Oct 2000
Volume 28, Issue 6 - Sep 2000
Volume 28, Issue 5 - Aug 2000
Volume 28, Issue 4 - Jun 2000
Volume 28, Issue 3 - Apr 2000
Volume 28, Issue 2 - Mar 2000
Volume 28, Issue 1 - Feb 2000
Volume 28, Issue 8 - 00 2000
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An Investigation of Characteristics of Roe's FDS by using the Compressible Euler Equations
Kim, Moon-Sang ; Kim, Hyung-Kuk ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 1~1
An Euler solver is developed by using the compressible Euler equations to investigate the characteristics of Roe's FDS. The inviscid fluxes are calculated by Roe's FDS and the second order accuracy in space is preserved by using the MUSCL approach and Albada's min-mod flux limiter. Beam & Warming's approximately factorized implicit scheme is implemented to increase the time step margin. In general the Roe's FDS shows the high accurate solutions compared with the other upwind scheme's solutions. But it has some handicap to generate the shock instabilities called carbuncle phenomena in high speed flow field. Many people can avoid this kind of unphysical situations by fixing the entropy conditions. Unfortunately fixing the entropy condition can degrade the solution accuracy because of additional numerical viscosity In other words, the merit of Roe's FDS can be lost. In this paper, the three different flowfields (transonic, supersonic, and hypersonic) are simulated to investigate the characteristics of the pure Roe's FDS. This research shows that the wall boundary conditions imposed on the problems strongly influence the results of the numerical flowfield analysis.
Experimental investigation of the turbulent wake past a symmetrical airfoil
Yoon, Joon-Yong ; Kwon, Woo-Chul ; Yoo, Hong-Hee ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 10~10
Detailed measurements of the mean velocities and turbulence quantities in the wake of a symmetrical NACA0012 airfoil have been made in the subsonic wind tunnel using hot-wire probes. The Reynolds number based on chord length was about
. Measurements were carried out at four downstream stations(0.033c, 1.0c, 2.0c, 3.0c) for various angles of attack. The results presented in this study include mean velocity, turbulent stresses, and turbulent kinetic energy. It is shown that mean velocity and turbulent quantities are strongly affected by an angle of attack. Thus, the points of the maximum value for the mean velocity and turbulent quantities are moved up in normal direction as increasing an angle of attack. The measurements reveal that the mean velocities and turbulent quantities are still affected by test model at the last measurement station(x/c=3.0). Results in this study are believed very useful for dynamic motion analysis and numerical analysis.
On The Developing Process of A Steady Supersonic Flow in A Shock Tube
Lee, Hee-Joon ; Park, Dong-Gyun ; Chang, Se-Myong ; Chang, Keun-Shik ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 17~17
Development of the steady supersonic flow from the moving shock wave in the KAIST shock tube is studied experimentally and numerically. Helium gas is used to obtain the initial incident shock wave of Mach number 2.59. A supersonic nozzle designed by the characteristic theory is installed inside the KAIST shock tube. The flow is impeded by the reflected shock wave, which is formed unavoidably when the incident shock wave collides with a blunt body model in the test section, before it is accelerated to a steady supersonic flow to form a standing bow shock wave in front of the model. Numerical analysis is also performed to simulate the process of establishing a standing bow shock wave from the initial moving shock wave in front of the blunt body.
Numerical Calculation of the Effect of Spanwise Pressure Gradient on the 3DTBL with an Embedded Longitudinal Vortex
Lee, In-Sub ; Ryou, Hong-Sun ; Lee, Seong-Hyuk ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 24~24
In this paper, the main objective is to investigate the effects of spanwise pressure gradient on the three dimensional turbulent boundary layer(3DTBL) with an embedded longitudinal vortex. The numerical calculations were carried out for the 3DTBL including a longitudinal vortex, which were clockwise and counter-clockwise rotating, by using the Reynolds stress model of Launder, Reece and Rodi(LRR) for the pressure-strain correlation terms. The governing equations were discretized by the finite volume method and SIMPLE algorithm was used to calculate the pressure field. The calculated results for clockwise vortex without the spanwise pressure gradient were compared with the experimental data of Pauley and Eaton. It is found that the clockwise vortex affected by the spanwise pressure gradient is shifted to the right-hand side and, as a result, the negative secondary vortex develops near the wall. In the case of counter-clockwise vortex, the region affected by the negative primary vortex is gradually increased by the pressure gradient, and vortex core disappears due to the turbulent diffusion. The turbulent normal stresses are enhanced at the vicinity of the wall due to the spanwise pressure gradient.
Experimental, Numerical Study on Flowfield around a High Speed Train
Hwang, Jae-Ho ; Lee, Min-Seop ; Lee, Dong-Ho ; Kim, Chong-Am ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 32~32
1/20 scale wind tunnel tests are performed about one configuration at 8 different flow conditions and numerical analysis are performed for eight different shapes. In order to study effect of Reynolds number and ground simulation on the experimental results, 4 wind speeds and tangential blowing technique at ground are chosen for the experiments. By measuring surface pressures, the effects of the Reynolds number variation and the ground simulation is presented. Solutions of 3 dimensional Navier-Stokes equations are obtained using FDS for the spatial discretization and AF-ADI for the time integration. Current computational results are verified with the experimental results, and after the numerical analysis of the eight different cases, it is shown that the dependency of the pressure drag on existence of skirt, sectional shape and nose length is clarified.
Computation of Two-Dimensional Compressible Navier-Stokes Equations on Hybrid Grids Using Newton-GMRES Method
Choi, Hwan-Seok ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 40~40
An efficient Newton-GMRES algorithm is presented for computing two-dimensional steady compressible Navier-Stokes equations on unstructured hybrid grids. The scheme is designed on cell-centered finite volume method which accepts general polygonal meshes. Steady-state solution is obtained with pseudo-transient continuation strategy. The preconditioned, restarted generalized minimum residual(GMRES) method is employed in a matrix-free form to solve the linear system arising at each Newton iteration. The incomplete LU factorization is used for the preconditioning of the linear system and the reverse Cuthill-McKee reordering is applied to reduce the fill-in during the factorization. The Spalart-Allmaras one equation turbulence model is fully coupled with tile flow equations to simulate turbulence effect. The accuracy, efficiency and robustness of the presently developed method are assessed on various test problems including laminar and turbulent flows over flat plate and airfoils.
Optimization of Wing In Ground Effect Craft
Chun, Ho-Hwan ; Kim, Hee-Jung ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 55~55
An optimisation study is carried out to generate a WIG configuration which gives the maximum lift and also satisfies the longitudinal height stability within the design constraints. For the analysis of the aerodynamic coefficients, a VLM method is used for the potential flow approximation. The optimization tool adopted is SQP(Sequential Quadratic Programming) which is one of nonlinear programming methods. The various optimum examples are shown such as the generation of the wing section, the determination of planform configuration and aspect ratio, and the determination of the side wing position. The effectiveness of the present optimization tool and results are demonstrated by showing good agreements with the experimental results.
Analysis of Kinked and Arc-Shaped Cracks in Anisotropic Materials by Using the Finite Element Alternating Method
Kim, Maan-Won ; Park, Jai-Hak ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 66~66
The stress intensity factors for a kinked crack or an arc crack in homogeneous anisotropic elastic materials were obtained by using the finite element alternating method. We used the solution of Zang and Gudmundson for the required analytic solution; they assumed a crack as continuous distribution of dislocations and solved the integral equations for the resultant forces applied on crack surfaces. In this case, the integral kernels in the equation contain a weak logarithmic singularity, which is very easy to handle in the numerical calculation. The proposed method can be applied to the analysis of an arbitrarily shaped curved crack embedded in an anisotropic finite plate. In order to verify the accuracy and the efficiency of the proposed method, we solved some problems and compared the results with those reported in other literature.
Optimization of Composite Laminated Structures by the Mixed Method
Park, Jung-Sun ; Lee, Soo-Yong ; Song, Seok-Bong ; Ryu, Suk-Kyu ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 74~74
A mixed method is presented to perform a discrete optimization of composite laminated structures. Nonlinear discrete optimization by genetic algorithm (GA) is disadvantageous to take long time to reach optimum since the GA uses a stochastic search method. The remedy for this disadvantage is to use the mixed method which combines the method of modified feasible directions(MFD) with the GA. Design variables in optimizing composite laminated structures are the number of ply and ply lamination angles. In this study, the composite structures are optimized by the mixed method and the optimization results are compared to the optimization results by the classical genetic algorithm. From the comparison, it is known that the mixed method converges to the optimum much faster than the conventional genetic algorithm only. The numerical results show that the mixed method is able to reach to the optimum value much closer and more effectively.
Theoretical Analysis Method of Composite Laminates(I) - Free-Edge Delaminations -
Kim, In-Kweon ; Kong, Chang-Duk ; Kang, Myung-Hoon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 81~81
A simplified method for the total strain energy release rate of free-edge delaminations in composite laminates is proposed. The interlaminar stresses are evaluated as an interface moment and interface shear forces that are obtained from the equilibrium equations at the interface between the adjacent layers. Deformation of an edge-delaminated laminate is calculated by using a generalized quasi-three dimensional classical laminated plate theory developed by the authors. The analyses are performed composite laminates subjected to uniaxial extension, with free-edge delaminations located symmetrically and asymmetrically with respect to the laminate midplane. Comparison of the results with a finite element solution using the virtual crack closure technique shows good agreement. The simple nature of the method makes it suitable for primary design analysis for the delaminations of laminated composite.
Input-shaped Lyapunov Tracking Control Law for Slew Maneuvers of Flexible Spacecraft
Jung, Dong-Won ; Kim, Sung-Pil ; Kim, You-Dan ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 87~87
Lyapunov tracking control law combined with input shaping method is proposed for slew maneuver of flexible spacecraft. Reference control input for slew maneuver is constructed by input shaping method. The input-shaped control input is used as a reference input for Lyapunov tracking controller. The reference input can be easily constructed using the natural frequencies and damping factors. The proposed method is demonstrated experimentally on a flexible space structure testbed. The experimental results show that the accurate slew maneuver is achieved without residual vibration.
A Study on the Dynamics of Inertial Measurement Sensor Using Levitation System
Park, Young-Woong ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 95~95
Gyros are used to detect inertial attitude of a moving system. But generally gyros are being composed of very complex and delicate gimbal structures and expensive components. Recently some detectors are developed which are different from the gimbal system. A levitation system is a magnetic substance position control system in magnetic field using electric magnetic force. In this paper, using levitation systems a 3-axis attitude detector is introduced to detect 3-axis attitudes angles. Additionally, a new technique obtaining 3-axis linear acceleration information is introduced. Finally, the dynamics of the magnetic substance which is a moving mass is introduced.
A study on the spray behaviour in the fuel spray with variable air/fuel ratio on the swirl flow field
Lee, Dong-Hun ; Han, Yeoung-Min ; Bae, Chung-Sik ; Choi, Jong-Soo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 102~102
The effects of swirl flow on the fuel spray characteristics were investigated under various air and fuel supply conditions through measurements of velocity, spray characteristics using APV(Adaptive Phase/Doppler Velocimetry) in a gas turbine combustor fuel module system.. The flow and spray characteristics such as structure of recirculation region, intensity of swirl flows, spray particle size, volume flux and number density were examined when swirl flow was induced by frontal devices. It was found that the mass increase of air supply toward center of the swirl flow is observed at downstream while the structure and size of recirculation has no change as the mass of supply air increase. Smaller fuel droplets were observed in the main axial stream and inside the recirculation zone when air supply increased. The interaction of air/fuel ratio and particle size coincide with SMD - We number relation.
An experimental study on the combustion performance of unlike impinging F-O-O-F type injector with LOX / Kerosene
Lee, Dong-Jin ; Park, Hee-Ho ; Kim, Yoo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 111~111
The optimum combustion chamber geometry of impinging split triplet injector(F-O-O-F) was proposed through the various experiments reacting cases using liquid oxygen and liquid kerosene in a uni-element model rocket. The designed operation condition for thrust and combustion pressure were 140lbf and 200psia, respectively. It is found that the vaporization loss of injector can be obtained by comparing the reacting and non-reacting cases by varying the oxidizer/fuel ratios.
Vortex Flow Control in Modern Aerodynamics
Sohn, Myong-Hwan ; Lee, Ki-Young ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 119~119
The fundamental phenomena and characteristics of vortex flow, that develop around the aerodynamic surfaces in the configuration components of the modem fighter aircraft with the enhanced maneuverability, are surveyed. The slender wing (or delta wing) with a sharp leading edge, the slender forebody, the LEX and the canard are the typical features of configuration component of the modem fighter aircraft. The flow generated around the components of high performance aircraft is a vortex dominated flow which significantly affects the aerodynamic characteristics by development, breakdown and interaction of vortex flows. Especially, we reviewed focusing on the control methods of vortex flow strength and vortex breakdown because vortex flow is a principal aerodynamic element in the design of enhanced maneuverability fighter aircraft and because it crucially affects the static and dynamic aircraft stability at high angle-of-attack.
Development of Shock Sensor Data Processing System for Rockets
Lee, Soo-Jin ; Kim, Joo-Nyun ; Ma, Keun-Su ; Lee, Jae-Deuk ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 131~131
A development of shock sensor data processing system that will be brought on-board the KSR(Korea Sounding Rocket)-III is introduced. Shock sensor processing system gathers shock data when special events, stage separation and launch, take place. Shock data to be transmitted is very massive compared to other sensors of the rocket. On account of constraints in transmission data rate and data channel number, it is mostly unable to transmit acquired massive shock sensor data from a flying rocket to ground station in real time. The primary goal of this paper is to describe a new approach to the development of a shock sensor data processing system which can overcome those constraints and execute its mission with success.
A Study on the Thermal Analysis and Insulation of KSR-III
Lee, Joon-Ho ; Oh, Bum-Seok ; Park, Jeong-Joo ; Cho, Gwang-Rae ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 138~138
Thermal analysis of KSR-III has been studied to calculate the surface heat transfer and temperature, with which thermal safety of rocket structures is investigated. In the present study, the honeycomb sandwich structure of nose fairing, which is one of the typical multi-layer structures of KSR-III, is thermally analyzed. In addition, the fin tip roll thruster case is thermally analyzed, considering aerodynamic heating, radiation from rocket plume and prelaunch heating concurrently. Some parts of structures are insulated to thermally protect the surface itself and inner payloads.
Status and Prospect of MAVs
Ahn, Jon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 28, issue 7, 2000, Pages 145~145