• International Journal of Aeronautical and Space Sciences
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• v.18 no.1
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• pp.17-27
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• 2017

The treatment of rotor wake has been a critical issue in the field of the rotor aerodynamics. This paper presents a new free wake model for the unsteady analysis for a wind turbine. A blade-wake-tower interaction is major source of unsteady aerodynamic loading and noise on the wind turbine. However, this interaction can not be considered in conventional free wake model. Thus, the free wake model named Finite Vortex Element (FVE hereafter) was devised in order to consider the interaction effects. In this new free wake model, the wake-tower interaction was described by dividing one vortex filament into two vortex filaments, when the vortex filament collided with a tower. Each divided vortex filaments were remodeled to make vortex ring and horseshoe vortex to satisfy Kelvin's circulation theorem and Helmholtz's vortex theorem. This model was then used to predict aerodynamic load and wake geometry for the horizontal axis wind turbine. The results of the FVE model were compared with those of the conventional free wake model and the experimental results of SNU wind tunnel test and NREL wind tunnel test under various inflow velocity and yaw condition. The result of the FVE model showed better correlation with experimental data. It was certain that the tower interaction has a strong effect on the unsteady aerodynamic load of blades. Thus, the tower interaction needs to be taken into account for the unsteady load prediction. As a result, this research shows a potential of the FVE for an efficient and versatile numerical tool for unsteady loading analysis of a wind turbine.

• International Journal of Aeronautical and Space Sciences
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• v.12 no.2
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• pp.93-114
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• 2011

The current status of Canadian research on rotor-based actively controlled technologies for helicopters is reviewed in this paper. First, worldwide research in this field is overviewed to put Canadian research into context. Then, the unique hybrid control concept of Carleton University is described, along with its key element, the "stiffness control" concept. Next, the smart hybrid active rotor control system (SHARCS) projected's history and organization is presented, which aims to demonstrate the hybrid control concept in a wind tunnel test campaign. To support the activities of SHARCS, unique computational tools, novel experimental facilities and new know-how had to be developed in Canada, among them the state-of-the-art Carleton Whirl Tower facility or the ability to design and manufacture aeroelastically scaled helicopter rotors for wind tunnel testing. In the second half of the paper, details are provided on the current status of development on the three subsystems of SHARCS, i.e. that of the actively controlled tip, the actively controlled flap and the unique stiffness-control device, the active pitch link.

• Journal of Satellite, Information and Communications
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• v.8 no.1
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• pp.35-39
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• 2013

Space technology is a core technology which is emerging as the most competitive industry in the 21st century. However, it is said that private enterprises may have some limitations to run the space business independently because the space industry requires not only to enormously spend the amount of investment at the beginning stage of business but also to have lots of difficulties to get the amount of investment in the short period of time. Therefore, the advanced countries of having the space industry such as America, Japan, France and so on have been developing the space technologies through the help of their governments to some level at the beginning stage of business. Korea established the space development promotion law in 2005. Also Korea has been making efforts to correct the national space development middle and long term basic plans. However, while Korea becomes the 8th economic country in the world, Korea does not have a large enterprise which has ability to supply the domestic satellite demands, and to export satellites to foreign countries by developing satellites without having any help from foreign companies. Therefore, this paper described the activating scheme of satellite industry to efficiently carry out the Korea's space development mission, and to enforce the global competitive power.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.2
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• pp.202-209
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• 2008

Application of wind turbine generator system (WTGS) needs researches for performance prediction, pitch control, and optimal operation method. Recently a new type WTGS is developed and under testing. The notable feature of this WTGS is that it consists of two rotor systems positioned horizontally at upwind and downwind locations, and a generator installed vertically inside the tower. In this paper, a nonlinear simulation software developed for the performance prediction of the Dual Rotor WTGS and testing of various control algorithm is introduced. This software is hybrid in the sense that FORTRAN is extensively used for the purpose of computation and Matlab/Simulink provides a user friendly GUI-like environment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.12
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• pp.1162-1169
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• 2010

The dynamic balancing of a rotor system is needed to alleviate the imbalances originating from various sources encountered during blade manufacturing processes and environmental factors. This work aims at developing a comprehensive analysis system which consists of cumulative module of test D/B and selection of optimal control parameters. This system can be used for the dynamic balancing of helicopter rotors based on tracking results from the whirl tower test. For simplicity of the analysis, a linear relation is assumed between the balancing input parameters and the blade track responses leading to influence coefficients and thereby the rotor system identification is made. In addition, the balancing parameters of the individual blades are sought using the genetic algorithm and the effectiveness of the proposed method is demonstrated in comparison with the test results.