• Journal of Wind Energy
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• v.15 no.1
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• pp.11-20
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• 2024

As the generation capacity of floating offshore wind turbines increases, the wind load applied to each turbine increases. Due to such a high wind load, the capacity of transport equipment (such as tugboats or cranes) required in the transportation and installation phases must be much larger than that of previous small-capacity wind power generation systems. However, for such an important wind load prediction method, the simple formula proposed by the classification society is generally used, and prediction through wind tunnel tests or Computational Fluid Dynamics (CFD) is rarely used, especially for a concept or initial design stages. In this study, the wind load of a 10 MW class floating offshore wind turbine was predicted by a simplified formula and compared with results of wind tunnel tests. In addition, the wind load coefficients at each stage of fabrication, transportation, and installation are presented so that it can be used during a concept or initial design stages for similar floating offshore wind turbines.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.8
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• pp.30-36
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• 2002

Wind tunnel model has some difference in shape compared to the real flight vehicle because of model support system for testing. The support system can make some differences in the measured forces and moments to the flight test data. There are several correction methods involved such as cavity pressure correction and model support interference. Internal balance and belly sting support were used for this wind tunnel test and three types of model support correction methods, variable sting thickness method, dummy sting method, and wire support method, were compared. Variable sting thickness method is well matched with wire support method, which is known for almost interference free.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.10
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• pp.894-900
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• 2012

The purpose of this research is to investigate the dynamic roll-damping characteristics of a spin-stabilized projectile in wind-tunnel testing. In the present work, the high-speed wind-tunnel tests for the roll-damping measurements were conducted on a finned spin-stabilized projectile model in the Agency for Defense Development's Trisonic Wind Tunnel at spin rates about 8,000 rpm. The test Mach numbers ranged from 0.6 to 0.9, and the angles of attack ranged from 0 to +15 deg. The evaluation of the bearing friction parameter was also conducted to eliminate the tare damping moment from the aerodynamic damping moment.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.6 s.237
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• pp.755-762
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• 2005

To evaluate the aerodynamic efficiency of TR-S2 configuration designed by SUDC, wind tunnel tests of $40\%$ scaled model were done in KARI LSWT. The aerodynamic characteristics of plain and Semi-Slotted Flaperon were compared, and vortex generators were installed to improve flow pattern along the wing surface. Effects of the control surface such as elevator, rudder, aileron, and incidence angle of horizontal tail are measured for various testing conditions. Test results showed that Semi-Slotted Flaperon produced more favorable lift, lift/drag, and stall margins and application of vortex generator would be best choice to enhance wing performance. Longitudinal, lateral and directional characteristics of TR-S2 were found to be stable for the pitch and yaw motions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.45-48
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• 2005

Tile gust generator was designed for generating the gust field in the wind tunnel test of the scaled flexible wing model for validating gust response alleviation system. The ground operation test was performed for estimating the dynamic performance of tile gust generator before installing it in the wind tunnel for gust field measurement. The ground test results showed that the gust generator has sufficient dynamic capability to simulate the sinusoidal and random motion of the gust generator wing and thus can be used in the wind tunnel test related to gust.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.12
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• pp.1599-1606
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• 2011

It is possible to study the load characteristics of full-scale hingeless rotor with the changing of physical smallscaled configurations such as rectangular and paddle blades, and metal and composite hubs. In this study, a static test, and a ground and wind-tunnel test were carried out using small-scale rotor models. The static test was carried out to confirm structural stiffness, characteristics of inertia, natural frequency, and damping ratio of rotors, and the ground and wind-tunnel test was carried out to confirm the stability and aerodynamic characteristics under hovering and forward flight conditions. According to the test results, the vertical load in the case of a combination of a small composite hub with paddle blades was higher than that in the case of a metal hub with paddle blades at same condition. Further, it was confirmed that the restraint of the combination of composite hub can be more flexible than the metal hub for the motion of paddle blades.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.3
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• pp.240-247
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• 2009

Wind tunnel test for Electro-Optical Targeting System(EOTS) has been conducted to investigate the aerodynamic characteristics, especially the torque characteristics of the rotating parts to insure the enough actuator power during the actual operation. The influence of EOTS's complex configuration, such as the observation window, has been investigated by comparing with the results of the simplified models made of half sphere and the cylinder. It has been found that the position of the observation window of EOTS has an effect on surface pressure distribution and the torque characteristics of the rotating observation part.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.4
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• pp.476-482
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• 2016

In this study, a method using single Wheatstone bridge flexure has been presented to measure hinge moment acting on control surfaces of wind tunnel models. The structural simplicity of the flexure reduces difficulty regarding gauging and wire-routing, and also makes it feasible to install flexures even inside thin wings. Some flexures were designed and fabricated under typical aerodynamic loads in wind tunnel test, and the strains on the flexure according to applied loads were compared with the result of the analysis by finite element method. The relation between applied loads and output signals showed good linearity, and the standard deviation on the residual errors from linear equation obtained by least square method was within 1.0 % of the maximum design moments. In addition, the FEM analysis on the thickness of load-connecting part of the flexure showed that the sensitivity was improved as the thickness became thin as much as desired to avoid buckling.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.494-497
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• 2009

풍력터빈 블레이드 풍동시험의 경우 사용가능한 시험설비의 크기제한으로 인해 축소모델 사용이 불가피하며, 이로 인해 풍동시험에서는 실물 블레이드에 비해 10% 미만의 낮은 Re수에서 시험이 수행된다. 축소모델 블레이드 풍동시험 결과를 활용하여 실물 블레이드의 성능(토크)를 추정하기 위한 축소효과 보정기법을 2008년 제시하였으며, NREL Phase VI 모델 시험결과에 적용하였다. 당시 제시된 보정기법은 단일익형을 전체 블레이드에 사용한 사례이며 축소효과 보정을 위해 Re수에 따른 익형의 양력계수 변화만을 적용하였다. 본 논문에서는 당시 제안된 축소효과 보정기법을 익형의 양력계수 및 항력계수를 포함한 형태로 수정하였으며, 블레이드에 다수의 익형이 사용되었을 경우에 대해 확장하였다. NREL Phase VI 12% 시험모델의 경우 익형의 양력계수 기울기에 의한 보정량은 약 15% 정도이며, 항력계수 변화에 의한 보정량은 약 5% 정도로 나타났다. 블레이드에 다수의 익형이 사용되었을 경우 설계 또는 전산해석을 통해 구한 반경별 토크 함수를 적용하여 블레이드 축소효과를 보정할 수 있다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.1
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• pp.10-16
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• 2013

This paper discussed a procedure for noise certification of Aircraft and predicting the full scale over-flight noise of propeller from acoustic wind tunnel measurement of small scale propeller. Noise Certification Procedures is established from International Civil Aviation Organization(ICAO). The data manipulations are then discussed in extrapolation to simulation flight distance and flight simulation. One of the most important point of flight simulation is adjustments for differences between wind tunnel test conditions and flight test conditions. To simulated the noise level estimation procedure for noise data post-process, simulate procedures from data of the wind tunnel noise measurement and the flight noise measurement by using a 7kg degree UAV. This study confirmed an effectively noise estimation procedures by wind tunnel noise test and flight noise test.