• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1785-1790
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• 2010

To study the vortex induced vibrations the wind tunnel and the two story shear building were designed and built. The wind tunnel was designed to generate the wind speed up to 24 m/s, and the building was designed to have the two lowest natural frequencies within the range of the vortex frequencies generated by the wind tunnel. The resonance behaviors by the locking-on phenomena were observed during the wind tunnel tests of the shear building with the cylinder attached. From the locking-on phenomena observed it is found that the effects of the amplitudes and the frequencies of the cylinders should be considered on the forces generated by the vortex shedding.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.11
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• pp.9-17
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• 2006

The SNU MAV has been designed through studies on highly efficient aerodynamic shape and propulsion system. The configuration of the vehicle was determined from conventional empirical equations, iterative wind tunnel tests and flight tests. The propeller shape was optimized with the various thrust tests and RSM(Response Surface Method) to obtain the higher efficient propulsion system. It was certified that the MAV could fly for over 17 minutes with a 210mAh battery. In addition, it showed good flight characteristics in both stability and controllability.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.332-335
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• 2011

바람에 의해 발생하는 장대교량의 진동현상은 버펫팅과 와류진동 그리고 플러터 등으로 구분할 수 있으며, 특히 설계풍속에 해당하는 강풍에 안전한 교량을 설계하는 것이 주된 관심사항이다. 이러한 장대교량의 공기역학적인 안정성 검토에 사용되는 플러터 계수를 풍동실험을 통하여 산정하였다. 본 논문에서는 일반적인 플레이트 거더교의 강풍에 대한 안정성을 검토하기 위하여 풍동실험을 수행하였으며, 자유진동 기법과 강제진동 기법을 사용하여 추출한 플러터 계수를 비교하였다. 자유진동 기법은 교량단면에 초기변위를 주어 상하 및 회전 진동을 하는 교량단면의 변위를 측정한 후 system identification 기법으로 플러터 계수를 구하게 된다. 그리고 강제진동 기법은 상하방향의 강제진동과 회전방향의 강제진동 실험을 독립적으로 수행하여 교량단면에 작용하는 풍하중과 단면의 진동을 분석함으로써 플러터 계수를 추정하게 된다. 그리고 플러터 계수의 비교를 통하여 강제진동 기법과 자유진동 기법의 장단점을 분석하였다.

• Journal of Korean Association for Spatial Structures
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• v.6 no.1 s.19
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• pp.91-99
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• 2006

This paper presents wind pressure distribution on high-rise apartment buildings through wind-tunnel tests. In order to investigate wind-induced interference efforts on building claddings an apartment complex, which was damaged on the claddings during typhoon attack, was exampled and constructed as a scaled model. A series of wind tunnel tests using pressure models were performed in a boundary layer wind tunnel. The test results with and without interfering buildings were compared and discussed. It is observed that the wind pressure on buildings 105 and 106 with surrounding buildings shows highly negative, while the pressure without surrounding buildings were positive. Therefore the wind-induced interference effects should be taken into account in the design of claddings through wind-tunnel tests.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.8
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• pp.1091-1096
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• 2010

This study was conducted to provide reference data for designing an alarm system that can help prevent the overturning of a container crane under wind load. Two methods, namely, fluid-structure interaction (FSI) analysis and windtunnel test, were adopted in this investigation. To evaluate the effect of wind load on the stability of the crane, a 50-ton-class container crane that is widely used in container terminals was adopted as the analysis model and 19 values were considered as design parameters for wind direction. First, the wind-tunnel test for the reduced-scale container crane model was performed according to the wind direction by using an Eiffel type atmospheric boundary-layer wind tunnel. Next, the FSI analysis for the real-scale container crane was conducted using ANSYS and CFX. Then, the uplift force determined from the FSI analysis was compared with that determined from the wind-tunnel test. Finally, a formula to compensate for the difference between the results of the FSI analysis and the wind-tunnel test was proposed.

• Journal of Korean Society of Disaster and Security
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• v.6 no.2
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• pp.49-56
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• 2013

In this paper, used by the boundary layer wind tunnel test, have conducted a series of wind tunnel experiments, i.e. test the mean velocity profile regarding the surface roughness, turbulence intensity and power spectrum measured by augmentation device. After that, to provide data relevant for the preliminary design step of tall building hazard fluctuating wind loads may be obtained fluctuating pressure coefficients, fluctuating pressure spectrum, autocorrelation coefficients by the boundary layer wind tunnel test. From the results of experiments, this study can be obtained conclusions as follows. 1. We know the fact that the mean velocity profile and the turbulence intensity are well fitted natural wind flow in the boundary layer wind tunnel. 2. The satisfactory agreement of velocity spectrum can be obtained from the compare of fluctuating power spectrum and Von Karman spectrum. 3. We know the fact that the fluctuating pressure spectrums distributed peak at 0.01 Hz-0.1 Hz in the windward surfaces and at 0.1 Hz in the leeward surfaces. 4. We know the fact that the autocorrelation coefficients distributed stationary random processes with application time of hazard fluctuating wind loads.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.311-316
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• 2006

This study was carried out to analyze the effect of wind load on the structural stability of a container crane according to the change of the boom shape using wind tunnel test and provided a container crane designer with data which can be used in a wind resistance design of a container crane assuming that a wind load at 75m/s wind velocity is applied on a container crane. Data acquisition conditions for this experiment were established in accordance with the similarity. The scale of a container crane dimension, wind velocity and time were chosen as 1/200, 1/13.3 and 1/15. And this experiment was implemented in an Eiffel type atmospheric boundary-layer wind tunnel with $11.25m^2$ cross-section area. Each directional drag and overturning moment coefficients were investigated and uplift forces at each supporting point due to the wind load were analyzed.

• 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.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.2
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• pp.159-166
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• 2018

In this study, the internal structural design, dynamic characteristics and load analyses of the small scaled rotor blade required for LCH(Light Civil Helicopter) main rotor wind tunnel test were carried out. The test is performed to evaluate the aerodynamic performance and noise characteristics of the LCH main rotor system. Therefore, the Mach-scale technique was appled to design the small scaled blade to simulate the equivalent aerodynamic characteristics as the full scale rotor system. It is necessary to increase the rotor speed to maintain the same blade tip speed as the full scale blade. In addition, the blade weight, section stiffness, and natural frequency were scaled according to the Mach-type scaling factor(${\lambda}$). For the design of skin, spar, torsion box, which are the main components of the blade, carbon and glass fiber composite materials were adopted, and composite materials are prepreg types that can be supplied domestically. The KSec2D program was used to evaluate the section stiffness of the blade. Also, structural loads and dynamic characteristics of the Mach scale blade were investigated through the comprehensive rotorcraft analysis program CAMRADII.

• Journal of Ocean Engineering and Technology
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• v.5 no.2
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• pp.171-171
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• 1991