• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.1
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• pp.1-13
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• 2014

A new 5-MW floating offshore wind turbine moored by a spring-tensioned-leg was proposed for installation in about 50m water depth. Its substructure is a platform of the inverted conical cylinder type with massive ballast weight plate at the bottom. A 1:128 scale model was built for the preliminary engineering development. The model tests in waves and wind were carried out to estimate motion characteristics of this platform in the Ocean Engineering Wide Tank of the University of Ulsan. Its motions were measured and the RAOs were compared. The proposed floating offshore wind turbine showed a good stability and decent responses in waves, wind and operation of the wind turbine.

• Proceeding of KASS Symposium
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• 2006.05a
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• pp.91-101
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• 2006

We have conducted the study about the shelter effect against the wind by using the wind fence with various porosities and the measured distance from the wind fence, in three different types of it ; (Circle wind fence, Vertical wind fence, Horizontal wind fence) The shelter effect and turbulence characteristics of the selected wind barrier is throughly investigated by wind tunnel test. flow characteristics of velocities and turbulences behind wind fence were measured using hot-wire anemometer. we characterize the turbulence behind the wind fence by varying the porosity of 0 %, 20 %, 40%, and 60%, and the distances from the wind fence from 1 H to 9 H with maintaining the uniform flow velocity of 6 m/s. In addition, we investigated the overall characterization of the wind fence by measuring total of twenty eight points on the wind fence, which forms the lattice structure on it with seven points in lateral direction and four points in vertical direction. The results of analysis from the circle wind fence indicate that the degree of the turbulence is lowered and the velocity of the wind is decreased when the porosity of 40 % are used at the distance from 3 H to 9 H. On the other hand, the vertical, horizontal wind fence with the porosity of 20% is more advantageous at the distance of 2 H to 9 H. For the effectiveness of the wind fence depending on the position, the center part is the greatest and it decreases at the edges with 10 % to 30 % less than that of at the center.

• Proceeding of KASS Symposium
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• 2008.05a
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• pp.19-24
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• 2008

The thesis is for gust factor needing when calculate the wind resistance design. For the gust factor, to the membrane structural model, carry through the wind tunnel test and the static load test. Therefore, at first through the tensile test of the fabric material, designate the material of the membrane structural model. Then, to saddle, wave, arch and point four kinds of basic shape membrane structural models, carry on the wind tunnel test, determine their dynamic load and distortion on lateral direction. Finally, according to distort situation of the membrane structure in the wind tunnel test, carry on the static load experiment outside of the wind tunnel, calculate static load which corresponding with distort. According to dynamic load and the static load, figure out gust factor of these kinds of basic membrane structure.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.3
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• pp.230-236
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• 2012

The purpose of this research is to determine the calibration constants of the wind speed measurement systems required to calculate the wind tunnel velocity in the test section. In the present work, the aerodynamic calibration tests of the test section were conducted in the Agency for Defense Development's Low-Speed Wind Tunnel. The test speed ranged from 10 to 100 m/s with a reference pitot-static pressure probe. The validity of the calibration results was evaluated by comparing them with the previous calibration constants. The calibration results show that fair to good agreement is obtained with resonable accuracy.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.5
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• pp.637-643
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• 2019

Wind tunnel testing for flow-through model is necessary for performance prediction of an aircraft with air-breathing jet engine. Internal drag correction and wall correction are performed to acquire preciser wind tunnel test data. Many test runs are generally required to correct internal drag and wall interference in wind tunnel test. In this study we investigated more effective correction schemes using the response surface method. Even though the number of tests required for these schemes was much smaller than that for conventional methods, the differences between corrections using these schemes and conventional methods were similar level with the uncertainty of measurement except for the data near the boundaries.

• Wind and Structures
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• v.4 no.3
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• pp.213-226
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• 2001

Wind uplift rating of roofing systems is based on standardised test methods. Roof specimens are placed in an apparatus with specified table size (length and width) then subjected to the required wind load cycle. Currently, there is no consensus on the table size to be used by these testing protocols in spite of the fact that a table size plays a significant role in evaluating the performance. This paper presents a study with the objective to investigate the impact of table size on the performance of roofing systems. To achieve this purpose, extensive numerical experiments using the finite element method have been conducted to investigate the performance of roofing systems subjected to wind uplift pressures. Numerical results were compared with results obtained from experimental work to benchmark the numerical modeling. Required table size and curves for the determinations of appropriate correction factors are suggested. This has been completed for various test configurations with thermoplastic waterproofing membranes. Development of correction factors for assemblies with thermoset and modified bituminous membranes are in progress. Generalization of the correction factors and its usage for wind uplift rating of roofs will be the focus of a future paper.

• Wind and Structures
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• v.28 no.4
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• pp.215-224
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• 2019

Because of the particularity and complexity of direct air-cooling structures (ACS), wind parameters given in the general load codes are not suitable for the wind-resistant design. In order to investigate the wind loads of ACS, two 1/150 scaled three-span models were designed and fabricated, corresponding to a rigid model and an aero-elastic model, and wind tunnel tests were then carried out. The model used for testing the wind pressure distribution of the ACS was defined as the rigid model in this paper, and the stiffness of which was higher than that of the aero-elastic model. By testing the rigid model, the wind pressure distribution of the ACS model was studied, the shape coefficients of "A" shaped frame and windbreak walls, and the gust factor of the windbreak walls were determined. Through testing the aero-elastic model, the wind-induced dynamic responses of the ACS model was studied, and the wind vibration coefficients of ACS were determined based on the experimental displacement responses. The factors including wind direction angle and rotation of fan were taken into account in this test. The results indicated that the influence of running fans could be ignored in the structural design of ACS, and the wind direction angle had a certain effect on the parameters. Moreover, the shielding effect of windbreak walls induced that wind loads of the "A" shaped frame were all suction. Subsequently, based on the design formula of wind loads in accordance with the Chinese load code, the corresponding parameters were presented as a reference for wind-resistant design and wind load calculation of air-cooling structures.

• 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.

• Journal of Korean Society of Steel Construction
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• v.12 no.5 s.48
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• pp.495-502
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• 2000

In this study, the wind tunnel test for Kwangju World Cup Stadium with long span roof was carried out and its results were considered in the two roofs: one is the case of one roof, and the other is the case of two roofs which are identical. In this experiment, a 1/400-scale model was used. As a result of measuring wind pressure in the case of one roof and then two, when two roofs are set up, wind load for structural frame decreases by 35%, compared to that of one roof. These results show that the current criteria for wind loadings, which specify that wind pressure on the roof depends only on the altitude, have limitations for adoption, and a wind tunnel test is essential to design.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.3
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• pp.163-170
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• 2013

The correlation and interaction mechanisms between marine debris and the vegetation zone were studied on the Jinu-do natural beach of the Nakdong river estuary. Laboratory wind tunnel experiments were carried out under the wind-field and bottom-sand conditions using wind tunnel test equipment to investigate the sedimentation characteristics of wind-drift sand deposition around marine debris and the vegetation zone. The major environmental factors/loads considered in this study were the motion of sand by wind on the beach, deposition of marine debris, and change in the vegetation zone/line. When the marine debris was installed in the wind tunnel, deposition at the front of the structure appeared first by wind action, and then deposition developed from behind at 70% of the front ground level. In contrast, in the case of vegetation, the deposition phenomenon appeared first from behind the vegetation zone/line, and was 60% higher than the front. When the height of the debris and vegetation was the same, the required experimental time to bury the vegetation completely was about twice that of the marine debris.