• Journal of computational fluids engineering
• /
• v.16 no.1
• /
• pp.48-52
• /
• 2011

Aerodynamic analysis was done for a fuselage and wing configuration of a mid-sized aircraft using unsteady 3-dimensional Navier-Stokes solver. Various turbulent models including a transitional SST were used to observe a dynamic stall as well as cruise characteristics. Also, different mesh moving methods were evaluated. Flow hysteresis which causes dynamic stall was investigated through flow field investigations.

• 한국전산유체공학회:학술대회논문집
• /
• 2010.05a
• /
• pp.37-39
• /
• 2010

Aerodynamic analysis was done for a fuselage and wing configuration of a mid-sized aircraft using 3-dimensional Navier-Stokes solver. Various turbulent models including a transitional SST were implemented to observe a dynamic stall as well as cruise characteristics. Also, different mesh moving methods were evaluated. Flow hysteresis which causes dynamic stall was investigated through flow field investigations.

• Journal of Institute of Control, Robotics and Systems
• /
• v.8 no.8
• /
• pp.633-638
• /
• 2002

We study how the missile autopilot with three loop acceleration structure is related to the aerodynamic characteristics. First, the relationships between the response characteristics of wingless-tail controlled missile and aerodynamics are derived. Next the maximum allowable performance limit of autopilot and the design direction for a missile shape are indicated using the property of zero. The method proposed in this paper may give a help to the missile autopilot system design and determination of the shape of aerodynamic. Also, the validity of proposed method is demonstrated via numerical example.

• Journal of Advanced Marine Engineering and Technology
• /
• v.30 no.8
• /
• pp.877-884
• /
• 2006

The objective of this study is to investigate the aerodynamic characteristics of a vertical axis wind turbine blade as the basic study of a design of a vertical axis wind turbine. The lift and drag coefficients of the various shape of the vortical axis wind turbine blades are analyzed and compared using the CFD code Fluent. To validate the numerical analysis, the predicted results of the Fluent are compared with those of the Xfoil code and the experimental results. We conclude that the program Fluent can be used to predict the aerodynamics of the wind turbine blade. By comparing the predicted results of the aerodynamic characteristics of the different shape of the blades, an appropriate shape of the blade is suggested to design the vortical axis wind turbine blade.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.556-561
• /
• 2003

Flight bodies are subject to highly unstable and severe flow conditions during taking-off and landing periods. In this situation, the flight bodies essentially experience accelerating or decelerating flows, and the aerodynamic characteristics can be completely different from those of steady flows. In the present study, unsteady aerodynamic characteristics of an aerofoil accelerating at subsonic speeds are investigated using a computational method. Two-dimensional, unsteady, compressible Navier-Stokes simulations are conducted with a one-equation turbulence model, Spalart-Allmaras, and a fully implicit finite volume scheme. An acceleration factor is defined to specify the unsteady aerodynamics of the aerofoil. The results show that the acceleration of the subsonic aerofoil generally leads to a variation in aerodynamic characteristics and it is more significant at angles of attack.

• 한국신재생에너지학회:학술대회논문집
• /
• 2006.06a
• /
• pp.273-276
• /
• 2006

To generate electricity from wind energy, wind turbine generally has a rotor blade. Since this rotor blade is a kind of the rotating machinery, the wake from the rotor is very Important role in the side of the aerodynamic performances. Thus the study about wake is essential to analyze wind turbine aerodynamics. In this study wake characteristics are analyzed by hot-wire probe in the K.A.F.A(Korea Air Force Academy) wind tunnel. It is possible to analyze the wake characteristics by hot-wire probe from acquiring the velocity fluctuations at given positions in the flow. This velocity data are arranged by trigger signal at same azimuth of the blade in periodic manner of the rotor blade. From this various wake characteristics are found : radial and axial position of the tip vortex, vortex core characteristics in the flow etc.

• Journal of Wind Energy
• /
• v.5 no.1
• /
• pp.33-42
• /
• 2014

The new aerofoil, KA2 was designed to apply to the wind turbine blade. For the aerofoil, numerical analysis was performed to review aerodynamic characteristics like lift and drag coefficient. And they are verified with test data using the digital wind tunnel and test samples from 3D printer. The digital wind tunnel was developed to test wing in the small laboratory, and verified with test of NACA0012 airfoil. KA2 aerofoil is asymmetric, and has the thickness ratio of 14%, and 12 degree of AOA at the maximum lift coefficient of 1.3. In this paper, aerodynamic characteristics from numerical and test approaches will be proposed with AOA in detail. Therefore, this aerofoil will be used for the design of wind turbine blade.

• Journal of Power System Engineering
• /
• v.10 no.2
• /
• pp.22-28
• /
• 2006

Computer simulation of the air flow over an automotive vehicle is now becoming a routine process in automotive industry to assess the aerodynamic characteristics of a medium-size vehicle such as $C_d\;and\;C_1$ and aslo to investigate the possibility of improving aerodynamic performance of the vehicle as a preliminary design for the production line. Mainly due to its contribution in saving time and cost in the development of new cars, computer simulation of the air flow over a vehicle is usually done well before a production car is introduced to the market and in gaining more and more attention as powerful computer resources are getting readily available nowadays. To aerodynamically design a car is mainly related with reducing a drag coefficient of car. A well designed car usually has a $C_d$ value in the range of $0.3{\sim}0.4$. It is understandable that automotive industry is rushing to reduce a drag coefficient as reducing even a small fraction of the $C_d$ value can have an enormous overall impact on many areas. Actually, the present research model was able to achieve a $C_d$ value in the range of $0.3{\sim}0.36$ for flow velocities of $60km/h{\sim}100km/h$ by strategically removing the possible factor hazardous to lower $C_d$ value. Prediction of the medium-size vehicle aerodynamics using CFD was performed when an actual car model was in the development stage and three-dimensional modeling was also performed to optimize it as the best model in terms of the best aerodynamic performance.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.9
• /
• pp.823-831
• /
• 2011

According to the development of loading equipments, it is usual to change or replace the existing stores. It has been known that pylon-mounted under stores strongly affect aircraft dynamics characteristics due to the change of aerodynamics. To predict the aerodynamics and aero-elasticity is essentially requested with considering the configuration and shape of external stores during the development of aircraft and/or external stores. In this paper, computational fluid dynamics and computational structure dynamics interaction methodology are applied for prediction of aerodynamic characteristics for F-5 aircraft's horizontal tail with various shape of external stores. FLUENT and ABAQUS were used to calculate fluid and structural dynamics. Code-bridge was made base on the globally supported radial basis function to execute interpolation and mapping. As a result, even though the aeroelasticity of the horizontal tail slightly changes according to the shape of external store, the flutter was not occurred at the considered flight conditions in this study.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.18 no.1
• /
• pp.27-32
• /
• 2010

In this study, transonic flutter response characteristics have been studied for the AGARD 445.6 wing considering various turbulent models and several angle of attacks. The developed fluid-structure coupled analysis system is applied for flutter computations combining computational structural dynamics(CSD), finite element method(FEM) and computational fluid dynamics(CFD) in the time domain. The flutter boundaries of AGARD 445.6 wing are verified using developed computational system. For the nonlinear unsteady aerodynamics in high transonic flow region, DES turbulent model using the structured grid system have been applied for the wing model. Characteristics of flutter responses have been investigated for various angle of attack conditions. Also, it is typically shown that the current computation approach can yield realistic and practical results for aircraft design and test engineers.