• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.58.1-58.1
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• 2011

In this paper, the purpose is a study on structural analysis for offshore wind turbine using commercial code. Because offshore wind turbine is subjected to great wind and wave force, it is necessary to analyse the dynamics and minimize the response of wind turbine. The offshore wind turbine tower is modelled as a single degree of freedom and multi degree of freedom structure. It is assumed that the blades, nacelle are composed of concentrated masses.

• 대한건축학회논문집:구조계
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• 제35권7호
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• pp.157-164
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• 2019

The wind tunnel test makes it possible to predict the wind loads for the wind resistant design. There are many methods to evaluate wind loads from data obtained from the wind tunnel test and these methods have advantages and disadvantages. In this study, two of these methods were analyzed and compared. One is the wind load evaluation method by fluctuating displacement and the other is the wind load evaluation method considering vertical profile of fluctuating wind force. The former method is evaluated as the sum of the mean wind load of the average wind force and the maximum value of the fluctuating wind load. The latter method is evaluated as the sum of the mean wind load and maximum value of the background wind load, and the maximum value of the resonant wind load. Two methods were applied to the wind tunnel test to compare the evaluated wind loads according to the two methods, with a maximum difference of about 1.2 times. The wind load evaluated by the method considering vertical profile of the fluctuating wind force (VPFWF) was larger than the wind load evaluated by the method by fluctuating displacement (FD). Especially, the difference of the wind load according to the two methods is large in the lower part of the building and the wind load is reversed at a specific height of the building. VPFWF of evaluating resonant wind loads and background wind loads separately is more reasonable.

• 한국항해항만학회지
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• 제39권5호
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• pp.385-391
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• 2015

In offshore, various external forces such as wind force, tidal current and impulsive breaking wave force act on offshore wind tower. Among these forces, impulsive breaking wave force is especially more powerful than other forces. Therefore, various studies on impulsive breaking wave forces have been carried out, but the soil reaction are incomplete. In this study, the p-y curve is used to calculate the soil reaction acting on the offshore wind tower when an impulsive breaking wave force occurs by typhoon. The calculation of offshore wind tower against impulsive breaking wave force is applied for the multi-layered soil. The results obtained in this study show that although the same wave height is applied, the soil reaction generated by impulsive breaking wave force is greater than the soil reaction generated by wave force.

• 한국소음진동공학회논문집
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• 제22권12호
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• pp.1164-1171
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• 2012

Recently, researches related to the green energy generation systems have increased significantly. Among them wind turbines are the most spread practical green energy generation systems. In order to enhance the power generation capacity of the wind turbine blade, the length of wind turbine blade has increased. It might cause undesirable excessive dynamic loads. Therefore dynamic characteristics of a wind turbine blade system should be identified for a safe design of the system. In this study, the equations of motion of a wind turbine blade system undergoing gravitational force are derived considering wind force and pitch angle. Effects of wind speed, variation of pitch angle of the wind turbine blade, rotating speed, and the blade length on its stability characteristics are investigated.

• 한국해양공학회지
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• 제29권4호
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• pp.283-290
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• 2015

This paper presents the results of a numerical study on the towing characteristics of a barge under various wind conditions. First, stability criteria, including the wind force, were derived based on the linear motion equations of a towed vessel. The effect of the wind force on the towing stability was investigated using stability criteria. Next, towing simulations were carried out using a nonlinear time-domain simulation method. In this case, the towline was modeled as a simple spring-damper, and the wind force was computed using the wind coefficient from CFD calculations. Simulations were conducted for a barge under a constant towing speed and constant wind speed conditions. The effect of the wind direction on the slewing motion was also observed. In addition, a series of numerical simulations using variable wind speeds were performed for the present barge with and without a skeg.

• Wind and Structures
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• 제36권6호
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• pp.355-366
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• 2023

Although machine learning (ML) techniques have been widely used in various fields of engineering practice, their applications in the field of wind engineering are still at the initial stage. In order to evaluate the feasibility of machine learning algorithms for prediction of wind loads on high-rise buildings, this study took the exposure category type, wind direction and the height of local wind force as the input features and adopted four different machine learning algorithms including k-nearest neighbor (KNN), support vector machine (SVM), gradient boosting regression tree (GBRT) and extreme gradient (XG) boosting to predict wind force coefficients of CAARC standard tall building model. All the hyper-parameters of four ML algorithms are optimized by tree-structured Parzen estimator (TPE). The result shows that mean drag force coefficients and RMS lift force coefficients can be well predicted by the GBRT algorithm model while the RMS drag force coefficients can be forecasted preferably by the XG boosting algorithm model. The proposed machine learning based algorithms for wind loads prediction can be an alternative of traditional wind tunnel tests and computational fluid dynamic simulations.

• 한국해안해양공학회지
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• 제14권2호
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• pp.161-170
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• 2002

이어도 해양과학기지의 풍력을 검토하기 위하여 50m/s의 설계풍속에 대하여 풍동실험과 수치해석을 수행하였다. 해수면위 상부구조물의 축소모형(1/80)에 대하여 풍력 및 모멘트를 계측하고 풍력계수를 산출하여 수치해석 결과와 비교한 결과, 이들 결과들이 대체적으로 잘 일치함을 확인하였다 따라서, 본 풍동실험의 결과를 상부구조물의 내풍설계자료로 충분히 활용할 수 있을 것으로 판단된다 실험결과를 이용하여 상부구조물 전체에 작용하는 풍력 및 모멘트 값들과 그리고 불투과 부속시설(주 데크, 태양광 발전판, 헬기 이 착륙장)의 외장 설계풍압과 구조설계용 풍압을 제시하였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2014년도 춘계학술대회
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• pp.253-254
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• 2014

In offshore, various external forces such as wind force, wave force and impulsive breaking wave force act on offshore structures. Many researches about this forces are published. Kim and Cao(2008) published researche on wave force of vertical cylinder. Kim and Go(2013) performed research on the subgrade reaction by external forces. Among this forces, impulsive breaking force is more massive than other forces, especially. Therefore, the studies about impulsive breaking wave forces have been carried out. Chun and Shim(1999) analyzed dynamic behavior of cylindrical pile subjected to impulsive breaking wave force. In this study, when the impulsive breaking wave force acts on the offshore wind turbine, the subgrade reaction acting on the mono-pile of the offshore wind turbine is calculated by p-y curve. The calculation is carried out to the multi-layered.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2013년도 춘계학술대회
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• pp.273-274
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• 2013

최근 해상 풍력 발전이 개발됨에 따라 풍력발전타워는 더욱 거대해지고 있으며, 육상의 타워에 비해 파력과 흐름 등 다양한 외력에 노출되어있다. 이에 따라 해상 타워의 기초는 육상 타워 보다 더욱 안정성이 요구된다. 본 연구에서는 현재 관측된 최대 풍속인 60m/s가 해상풍력타워로 향하여 불 때, p-y 관계를 이용해, 원통형, 계단형, 원추형 타워의 기초에 작용하는 풍력과 파력을 해석 하였다.

• Wind and Structures
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• 제4권1호
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• pp.63-72
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• 2001

This paper presents results of a study on wind loads and wind induced dynamic response of bridge jointed twin-towered buildings. Utilizing the high-frequency force balance technique, the drag and moment coefficients measured in wind tunnel tests, and the maximum acceleration rms values on the top floor of towers, are analyzed to examine the influence of building's plan shapes and of intervals between towers. The alongwind, acrosswind and torsional modal force spectra are investigated for generic bridge jointed twin-towered building models which cover twin squares, twin rhombuses, twin triangles, twin triangles with sharp corners cut off, twin rectangles and individual rectangle with the same outline aspect ratio as the twin rectangles. The analysis of the statistical correlation among three components of the aerodynamic force corroborated that the correlation between acrosswind and torsional forces is significant for bridge jointed twin-towered buildings.