Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Society for Aeronautical & Space Sciences
Journal Basic Information
Journal DOI :
The Korean Society for Aeronautical & Space Sciences
Editor in Chief :
Volume & Issues
Volume 25, Issue 6 - Dec 1997
Volume 25, Issue 5 - Oct 1997
Volume 25, Issue 4 - Aug 1997
Volume 25, Issue 3 - Jun 1997
Volume 25, Issue 2 - Apr 1997
Volume 25, Issue 1 - Feb 1997
Selecting the target year
Computations of Hypersonic Flowfield around a Blunt Body with Roe's FDS and AUSM+ Schemes
Lee, Joon-Ho ; Rho, Oh-Hyun ; Byun, Woo-Sik ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 1~1
The hypersonic flowfield around a blunt body was numerically analyzed with 2D Navier-Stokes equations. Roe's FDS and AUSM+ schemes were used for spatial discretization and MUSCL was used fer higher order spatial accuracy. AE-ADI scheme was used for time integration. Roe's FDS needed an entropy fix to avoid the carbuncle phenomena near stagnation line. The entropy fix, however, decreased the solution accuracy in the boundary layer, so the value of entropy fix should be decreased in the boundary layer for the accurate solutions. The accuracy of the wall heat transfer solution was especially influenced by the amount of entropy fix. AUSM+ is one of the hybrid flux splitting schemes which were designed to combine the accuracy of FDS and the robustness of FVS. Numerical analysis with AUSM+ did not show the carbuncle phenomena. Furthermore, AUSM+ could give the accurate solutions in the boundary layer without boundary layer corrections.
An Experimental Study on the Intake Boundary Layer Diverters for Transonic Aircraft
Ki, Dock-Jong ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 14~14
It was tried in this paper to find out how the boundary layer diverters which prevent the boundary layer flow developed through the fuselage and strake from flowing into the air intake influence on the performance of the intake. The pressure recovery and distortion were measured at the engine face at various aircrat attitudes and airflow rates of the intake. The model was 1/7 scale of single engine aircraft with turbofan engine at the aft fuselage and bifurcated duct having intake at both side of the fuselage. It was found that intake performance is closely related with boundary layer diverter height and suitable height could be selected based on the intake performance at given maneuver and air flow rate conditions.
Flow Characteristics of Axisymmetric Jeta Forced by Annular Flows
Cho, Hyeong-Hui ; Lee, Chang-Ho ; Kim, Yeong-Seok ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 23~23
An experimental study is performed to investigate the characteristics of forced free jets using flow visualization, velocity and turbulence measurements. Axisymmetric shear layer around the jet is forced by co-flowing and counter-flowing secondary jets from/to an annular tube around the jet nozzle. The present study examines the effects of jet exit profiles; one is the uniform velocity distribution flow at the jet exit and the other is the fully developed turbulent tube flow. The jet potential core extends far downstream with co-flowing secondary jets due to inhibited vortex developing and pairing. For counter-flowing cases, the axisymmetric shear layer around the jet transits from convective instability to absolute instability for velocity ratios
for the uniform velocity jets. Consequently, the jet potential core length increases and the turbulence level in the jet core is reduced significantly. However, the instability of the shear layer does not change for the fully developed turbulent jets. The jets are controlled better with extension collars attached to the outside annular tube because the annular secondary flow is guided well by the extension cellars.
The Numerical Study of a 3-D Curved Duct Flow by Incompressible Navier-Stokes Code
Shin, Bo-Hyun ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 34~34
The numerical study of a curved duct flow has been made with a three-dimensional incompressible Navier-Stokes code developed using a pseudo-compressibility technique. With the main assumptions that the undisturbed flow is two-dimensional and the disturbed flow is periodic in the spanwise direction, computed flow field data for the modelled geometry has been compared with Rashed's measured data and analyzed to reveal the details of the vortex flow along the curved duct. The results of a detailed analysis of the computed vortex flow data indicate that if the axial momentum is reduced sufficiently by the upstream perturbation, the adverse axial pressure gradient near the entrance of the curved bend may generate a spiral node on the concave wall. The results also indicate that as the strength of the vortices increases in the axial direction, the vortices tend to move inboard to the symmetry plane.
Development of a New Gage for Simultaneous Direct Measurements of Skin Friction and Heat Flux
Baek, Seung-Woock ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 45~45
A new gage was developed for simultaneous direct measurements of skin friction and heat flux in supersonic gas flows. This gage is the combination of a non-nulling cantilever type floating element skin friction balance and a heat flux microsensor fabricated on the floating element. Active heating and cooling system is also included inside of the cantilever beam of skin friction balance so that the surface temperature of the floating element can be controlled as desired. Test was conducted in a supersonic wind tunnel. The nominal Mach number was 2.4, Reynolds number per meter was
with total pressure of 5.2 atm and total temperature of 300 K. Results of the test showed this new gage was quite reliable and could be used repeatedly. On the assumption that the floating element and its surrounding wall had the same surface temperature, the comparison with the computational results using the code GASP showed the differences were only 4% in skin friction and 3% in heat flux. Therefore, this new gage can be used for accurate simultaneous measurements.
Static Pressure Error Correction using the Correlation between Aerodynamic Analysis Model and Flight Test Data
Joh, Chang-Yeol ; Bae, Seung-Ho ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 50~50
PEC(Position Error Correction) flight tests were performed to identify the static pressure error source of the air data system in a turboprop aircraft. It was found that the position error was due to the improper location of current static port. Two of new static port candidates were selected through the correlation between flight test data and aerodynamic anaysis model. Another flight test was followed to verify these static port candidates and the results proved good selection. The series of position error correction works consequently revealed that the well-modeled aerodynamic analysis of low speed airplane using VSAERO and momentum theory for propeller slipstream effect had the capability of predicting surface pressure with satisfactory accuracy.
Computational and Experimental Investigation of the Flowfields about High Speed Train Configurations
Kim, In-Sun ; Chung, Jin-Deog ; Choi, Seong-Wook ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 56~56
A computational and experimental investigation has been conducted on two high speed train configurations, A-2 and TGV-K. Solutions of three-dimensional Navier-Stokes equations were obtained using implicit approximate factorization and upwind-biased finite volume algorithm on blocked grids. Wind tunnel tests were performed in a 1m by 0.75m KARI low speed tunnel. The computational and experimental results for the two high speed train configurations at the speed of 350Km/h, including surface pressure, flow visualization and lift and drag coefficients, were presented and analyzed.
Measurements of Transitional Flat-Plate Boundary Layer in a Blow-down Type Wind-Tunnel
Chang, Jin-Hyuck ; NamGoong, Ho-Woong ; Park, Seung-O ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 66~66
Transitional boundary layer on a flat plate placed in a blow down wind tunnel is examined from the point of view of intermittent production of turbulent spots. To investigate the transition from laminar to turbulent flow, time record of u-component oscillation near the wall is examined. The mean and fluctuating characteristics of the boundary layer are measured using the hot-wire anemometer system. It is confirmed that the intermittency factor in the transitional region of the boundary layer is expressed by one statistical similarity parameter. The skin friction over the transitional region is measured by LISF(Laser Interferometry Skin Friction meter) and is compared with the result of an empirical formula based on the intermittency factor. Using the measured skin friction, the mean velocity profiles are transformed in the wall coordinate over the transitional region to exhibit the velocity profile change from the Blasius profile to the log-law profile.
Optimization of Engine Design Parameters Using Approximating Functions
Oh, Se-Yoon ; Park, Chong-Yeong ; Hong, Yong-Shik ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 75~75
A comprehensive engine/airframe design method has been studied based on regression analysis and nonlinear optimization procedures. These procedures include the use of analytical/empirical design techniques, statistical methods, and nonlinear constrained optimization. The procedure applies statistics to independent cycle and airframe variables to determine a minimum number of mission analysis cases that must be run to create parametric equations for solutions for all variables and constraints under consideration. These equations can be considered to form multivariant surfaces as a function of the independent design variables and an optimum can be obtained on any solution surface by standard method.
An Alternative Computing Algorithm of the Penalized Weighted Residual Method for the Structural Dynamics
Ahn, Sung-Woo ; Cho, Jin-Yeon ; Kim, Seung-Jo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 83~83
In this paper, an alternative computing algorithm of the penalized weighted residual method is suggested which adopts step-by-step solving procedure like conventional time integration methods and is applied to the vibration analysis of the Timoshenko beam and the composite Mindlin plate. By the proposed computing procedure, it is possible to use the penalized weighted residual method with the saving of computer's memory compared to the direct solving procedure of the full space-time domain. According to the purpose of users, the direct solving procedure of full space-time domain or the step-by-step sequential solving procedure can be chosen in application of the penalized weighted residual method. Especially, the step-by-step sequential solving procedure can be effectively used in a conventional computing environment with small memory like desktop computer. To obtain a stable solution, a study is carried out and as a result, it can be known that the reduced integration in time domain gives an unconditionally stable solution even in the stiff systems frequently encountered in structural dynamics.
Viscoelastic Process-Induced Residual Stress Analysis on the Thick Composite Cylinder
Kim, Yeong-Kook ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 93~93
In this paper a viscoelastic analysis on the process-induced residual stress of thermoset matrix fiber-reinforced composite cylinder structure is presented. The material used for fabrication is AS4/3501-6 made by Hercules Inc. The material characteristics during cure was modeled in thermorheologically complex manner by a series of stress relaxation tests for several degree of cure states of 3501-6 epoxy. A finite element method is employed to analyze the cross-ply cylindrical structure, and the results are shown at the chosen time from the manufactiurer's recommanded cure cycle to enhance the understanding the mechanism of residual stress developments. The chemical shrinkage effect is also considered to examine its effect on the final residual stresses. All the results are compared with the elastic solutions. It was shown that the stress relaxation behavior as well as the chemical resin shrinkage had a great influence on the final residual stresses.
Numerical Cure Simulation of Thick Composite Structures by Finite Element Method
Park, Hoon-Cheol ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 104~104
A finite element code is developed for cure simulation of thick composite structures. To obtain time history of temperature distribution during cure, 6 node 6 DOF element is adopted for finite element formulation and Trapezoidal rule is used for time integration. Other than the previous codes based on finite difference method, this code can easily model structures with arbitrary shapes including any type of mandrel used for cure set-up. This code will provide distributions of temperature and degree of cure through the structure thickness, so that these distributions can be used fur the analysis of cure induced stress in composite structures.
A Study on Optimal Torque Shaping for Slewing and Vibration Suppression of Flexible Structures
Suk, Jin-Young ; Moon, Jong-Yun ; Kim, You-Dan ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 110~110
In this paper, optimal torque shaping based on trigonometric series expansion of modified bang-bang input is obtained for simultaneous slewing and vibration suppression of flexible structures using reaction wheel and piezoelectric actuator. After analyzing the vibration energy with respect to various parameters, analytic expressions of performance indices and their derivatives are derived in modal space and state space. Gain set of tracking controller adopting Lyapunov stability theory is optimized to guarantee accurate targeting far the system with/without external disturbances. It is verified through numerical simulation that flexible structure shows good-tracking capability and excellent vibration suppression adopting open-loop torque shaping. Moreover, Lyapunov tracking control law shows no more performance degradation during/after maneuver even in the presence of external disturbance.
An Anti-Windup Controller Design for Two Stage Sounding Rocket
Choi, Hyung-Don ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 124~124
An anti-windup controller far the attitude control of two stage sounding rocket has been designed. Once the actuator comes up to saturation limits, a feedback signal is generated in this controller from the difference of the compensator output and the actuator control input and used to make the actuator work in the linear ranges. When this type of controller was applied to the two stage sounding rocket attitude control system, a remarkable improvement has been made in the control performance as compared with the PID controller case. The performance of this anti-windup controller was sensitive to the variations of control gains, and thus, a modified anti-windup controller has been also proposed to compensate for this matter.
Implementation of a Nonlinear Autopilot For Skid-To-Turn Missiles via Neural Networks
Song, Yong-Kyu ; Koh, Gi-Ok ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 134~134
High performance missile autopilots often require full states and assume some dynamic inversion. Some states of missile dynamic systems such as the angle of attack and sideslip angle, however, are not measurable. Thus for feedback the information from the inertial measurement unit is employed or the state estimator should be constructed. This paper presents a neural network state estimator for this purpose and implements a nonlinear autopilot for Skid-To-Turn (STT) missiles using these state estimates. The missile model considered in this paper exhibits strong nonlinearties including the coupling between pitch and yaw channels under the assumption of perfect roll-stabilization. In addition to neural network state estimator, a partial linearizing controller, which is a key element in the dynamic inversion, is also constructed through neural networks. With some dynamic compensators, the autopilot is implemented in a hybrid manner and shows good simulation results under some aerodynamic uncertainties.
Analysis of Landing Characteristics of an Aircraft with ABS using Nonlinear and Equivalent Linear Approaches
Kim, Doo-Man ; Lim, Kyoung-Ho ; Hwang, Jai-Hyuk ; Ko, Ung-Dae ; Park, Myoung-Ho ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 142~142
The landing characteristics of an aircraft with optimal anti-skid brake has been analyzed and compared in this study using nonlinear and equivalent linear models. The landing characteristics is affected by the coupling between the vertical and horizontal motion of the landing gear during landing and taxing. Thus, the equations of motion of the landing gear to analyze the landing characteristics have been derived in this research. It has been found by a series of numerical simulation that there is a distinct discrepancy between two models in terms of the motion characteristics and internal farces of the landing gear, whitens no discrepancy in terms of the landing distance. Therefore, it may be concluded that the nonlinear model of the landing gear is more appropriate for the analysis of landing characteristics than the equivalent linear model because the nonlinear model can explain much closely to the real phenomena of landing.
East/West Station Keeping of Geostationary Satellite using Harmonic Basis Function
Kim, Dae-Sik ; Kim, Chun-Hwey ; Park, Bong-Kyu ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 154~154
The E/W station keeping elements or GEO(Geostationary Orbit) satellite varies not only secular but also periodic due to perturbation forces. We model the HBF(Harmonic Basis Function) of this variations and apply it to E/W station keeping of KOREASAT. The result of our model is compared with that determined by E/W station keeping using linear polynomial method. It is found that longitude using HBF has overestimated value higher than result using linear polynomial method, however drift rate is carried out similar value each other. In both of linear and nonlinear method we can control the eccentricity vector in tolerance circle. Additionally, we show that one can predict the effects of post-maneuver drift element and eccentricity element without carrying out numerical integration, and thus saving computation time, when the HBF is used.
A Study on the Measurement of Roll Moment of Inertia of a Large Cylindrical Shell
Yang, Myung-Seog ; Lee, Yeol-Wha ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 163~163
The mass properties of an aircraft and a missile, which are the mass, the center of gravity and the moment of inertia, are estimated theoretically and verified experimentally. The experimental determination of mass characteristics is performed by the pendulum method and the knife edge method. The existing methods may have the error by the friction at a rotating part. Also, they have the risk like the drop and the overturn of a specimen because it is hung by the fixture on the ceiling. In order to solve these problems, the measurement method of the roll moment of inertia for a large cylindrical shell using the air bearing technique is proposed in this study. The modified air bearing is manufactured, and the roll moment of inertia of the standard specimen is measured by this method. The standard specimen is simplified to diminish the error in the theoretical estimation, and the test result is a good agreement with the theoretical estimation.
Guidance Methods of Missile
Ahn, Jo-Young ; Cho, Kyu-Pil ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 171~171
Control Technology of Missile
Jun, Byung-Eul ; Song, Chan-Ho ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 178~178
Guidance and Control System of Satellite Launcher
Choi, Hyung-Don ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 6, 1997, Pages 184~184