• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.3
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• pp.40-46
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• 1999

Aerodynamic performance and starting characteristic of wind turbine blade are important factors that determine the whole system as rated power, operating method, etc. Therefore, starting characteristic according to aerodynamic performance, wind speed and blade pitch angle should be examined while wind turbine blade is designed. In this study, the aerodynamic analysis program of 750㎾ class horizontal axis wind turbine blade was developed and to certify this program, the aerodynamic performance of the commercialized blade was analyzed with it. The analysis result was corresponding to the value presented from manufacturer. And the starting analysis program was developed on the basis of the developed aerodynamic analysis program and starting analysis was performed. As a result, it was confirmed that variable speed operation and variable pitch control are profitable to wind turbine used in low wind speed as our country.

• Journal of Mechanical Science and Technology
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• v.14 no.12
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• pp.1358-1364
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• 2000

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.448-451
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• 2008

KARI is developing a satellite launch vehicle that is called KSLV(Korea Space Launch Vehicle)-I. During the flight, launch vehicles are exposed to aerodynamic heating conditions while flying at high Mach numbers in the atmosphere. KARI constructed Aerodynamic Thermal Simulation Facility to simulate aerodynamic heating on the ground. ATSF is a facility that can simulate given temperature profile using about 4,000 halogen heaters on fairing model. Aerodynamic heating profile is got from result of thermal analysis using MINIVER, Thermal Desktop, and SINDA/FLUINT. Aerodynamic heating test of fairing of KSLV-I was done using engineering model of payload fairing and Aerodynamic Thermal Simulation Facility. It was found that thermal analytic results show good agreement with aerodynamic heating test results within 6$^{\circ}$C at fairing inner surface. Also it was confirmed that maximum temperature of fairing nose-cone inner surface during flight is lower than allowable temperature limit.

• Aerospace Engineering and Technology
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• v.12 no.1
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• pp.73-80
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• 2013

In this study, a numerical analysis based on CFD methods has been conducted to predict the aerodynamic coefficients and aerodynamic loads of KSLV-II configuration designed at the system design phase. By the effects of exclusion of engine cowls of prior configuration, axial force and normal force decreased and center of pressure was much moved to the nose direction. Also, aerodynamic loads at flight and on the launch pad were predicted for structural load analysis. The computed results will be used for mission analysis and structural analysis at the next design phase.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.333-343
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• 1999

When a high speed train enters a tunnel, wind speed passing through the train in a tunnel section becomes higher due to the reverse flow to the direction of the train. The higher wind speed gives more aerodynamic forces to the pantograph on the train. Therefore, it is necessary to perform aerodynamic and dynamic analyses in order to check whether the current collection of the high speed train, entering the tunnel, still remain permissible or not. In this paper, the aerodynamic analysis has been performed under the assumption that a high speed train at 300 km/h enters a tunnel whose cross sectional area Is 107/㎡ and length is 1000m. In consideration of the aerodynamic analysis results, the dynamic analysis has been performed based on the catenary and pantograph dynamic models in SEOUL-PUSAN high speed rail, using the GASENDO developed by RTRI. In addition, the fatigue life of the contact wire has been reviewed using the Goodman diagram. Based on the analysis results, it is concluded that the increase of the aerodynamic forces on the pantograph in the tunnel section shall not affect characteristics of current collection adversely except that motions of the pantograph may be constrained by bump-stops.

• Journal of the Korea Society for Simulation
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• v.28 no.1
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• pp.49-56
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• 2019

In this study aerodynamic characteristics of guided gliding type ammunition were investigated by using a computational analysis and wind tunnel test. Missile DATCOM, a semi-empirical method, and a FLUENT, a computational fluid dynamics analysis program, were used for computational analysis. For a guided gliding type ammunition, aerodynamic characteristics were investigated by calculating lift force, drag force, pitching moment and etc. Aerodynamic characteristics of guided gliding type ammunition are completely different from those of conventional ammunition. The results obtained from the computer analysis are similar to those obtained from the wind tunnel test. Although the pitch moment values obtained by the semi-empirical method were slightly different from the wind tunnel test results, the overall computer analysis results showed trends and values similar to the test results. In this study, aerodynamic characteristics of guided gliding type ammunition were identified and it found that semi-empirical method can be applied to analyze the aerodynamic characteristic in the initial design of guided gliding ammunition.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2A
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• pp.97-104
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• 2011

This study presents the aerodynamic admittance function of bridge girder under turbulent flow generated from wind velocity spectrum measured at bridge site. Three dimensional buffeting analysis of concrete cable-stayed bridge were performed considering aerodynamic admittance functions obtained from four different methods. It is revealed from the analysis that vertical buffeting responses considering proper aerodynamic admittance functions were just half of that neglecting aerodynamic admittance function. Grid turbulence was found to relatively lower the aerodynamic admittance function at low frequency range, and to underestimate the buffeting wind forces. It is recommended to use the aerodynamic admittance function evaluated from flutter derivatives or measured at active turbulence in order to properly predict the buffeting responses of bridges.

• 한국전산유체공학회:학술대회논문집
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• 2006.10a
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• pp.28-29
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• 2006

Computational approaches for the aerodynamic design and optimization are introduced. In this paper the aerodynamic design methods and applications, which have been applied to various aerospace vehicles at Konkuk University, are introduced. It is shown that system approximation technique reduces computational cost for CFD analysis and improves efficiency for the design optimization process.

• Wind and Structures
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• v.6 no.2
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• pp.141-150
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• 2003

This paper presents galloping analysis of multiple-degree-of-freedom (MDOF) structural roofs with multiple orientations. Instead of using drag and lift coefficients and/or their combined coefficient in traditional galloping analysis for slender structures, this study uses wind pressure coefficients for wind force representation on each and every different orientation roof, facilitating the galloping analysis of multiple-orientation roof structures. In the study, influences of nonlinear aerodynamic forces are considered. An energy-based equivalent technique, together with the modal analysis, is used to solve the nonlinear MDOF vibration equations. The critical wind speed for galloping of roof structures is derived, which is then applied to galloping analysis of roofs of a stadium and a high-rise building in China. With the aid of various experimental results obtained in pertinent research, this study also shows that consideration of nonlinear aerodynamic forces in galloping analysis generally increases the critical wind speed, thus enhancing aerodynamic stability of structures.

• The KSFM Journal of Fluid Machinery
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• v.14 no.2
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• pp.29-34
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• 2011

Aerodynamic torque of wind turbine is highly nonlinear due to the nonlinear interactions between wind and blade. The aerodynamic nonlinearity is represented by nonlinear power and torque coefficients which are functions of wind speed, rotational speed of rotor, and pitch angle of blade. It is essential from the viewpoint of understanding and analysis of dynamic characteristics for wind turbine to linearize the aerodynamic torque and define aerodynamic nonlinear parameters as derivatives of aerodynamic torque with respect to the three parameters. In this paper, a linearization method of the aerodynamic torque from power coefficient is presented through differentiating it by the three parameters. And steady-state values of three aerodynamic nonlinear parameters according to wind speed are obtained and their nonlinear characteristics are investigated.