• 제목/요약/키워드: Wind load condition

검색결과 187건 처리시간 0.027초

Effect of Load Condition on Turning Performance of a VLCC in Adverse Weather Conditions

  • Zaky, Mochammad;Yasukawa, Hironori
    • Journal of Advanced Research in Ocean Engineering
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    • 제4권2호
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    • pp.53-65
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    • 2018
  • The load condition significantly influences ship maneuverability in calm water. In this research, the effect of the load condition on turning performance of a very large crude oil carrier (VLCC) sailing in adverse weather conditions is investigated by an MMG-based maneuvering simulation method. The relative drift direction of the ship in turning to the wave direction is $20^{\circ}-30^{\circ}$ in ballast load condition (NB) and full load condition (DF) with a rudder angle $35^{\circ}$ and almost constant for any wind (wave) directions. The drifting displacement in turning under NB becomes larger than that under DF at the same environmental condition. Advance $A_d$ and tactical diameter $D_t$ become significantly small with an increasing Beaufort scale in head wind and waves when approaching, although $A_d$ and $D_t$ are almost constant in following wind and waves. In beam wind and waves, the tendency depends on the plus and minus of the rudder angle.

Wind loads and load-effects of large scale wind turbine tower with different halt positions of blade

  • Ke, Shitang;Yu, Wei;Wang, Tongguang;Zhao, Lin;Ge, Yaojun
    • Wind and Structures
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    • 제23권6호
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    • pp.559-575
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    • 2016
  • In order to investigate the influence of different blade positions on aerodynamic load and wind loads and load-effects of large scale wind turbine tower under the halt state, we take a certain 3 MW large scale horizontal axis three-blade wind turbine as the example for analysis. First of all, numerical simulation was conducted for wind turbine flow field and aerodynamic characteristics under different halt states (8 calculating conditions in total) based on LES (large eddy simulation) method. The influence of different halt states on the average and fluctuating wind pressure coefficients of turbine tower surface, total lift force and resistance coefficient, circular flow and wake flow characteristics was compared and analysed. Then on this basis, the time-domain analysis of wind loads and load-effects was performed for the wind turbine tower structure under different halt states by making use of the finite element method. The main conclusions of this paper are as follows: The halt positions of wind blade could have a big impact on tower circular flow and aerodynamic distribution, in which Condition 5 is the most unfavourable while Condition 1 is the most beneficial condition. The wind loads and load-effects of disturbed region of tower is obviously affected by different halt positions of wind blades, especially the large fluctuating displacement mean square deviation at both windward and leeward sides, among which the maximum response occurs in $350^{\circ}$ to the tower top under Condition 8; the maximum bending moment of tower bottom occurs in $330^{\circ}$ under Condition 2. The extreme displacement of blade top all exceeds 2.5 m under Condition 5, and the maximum value of windward displacement response for the tip of Blade 3 under Condition 8 could reach 3.35 m. All these results indicate that the influence of halt positions of different blades should be taken into consideration carefully when making wind-resistance design for large scale wind turbine tower.

사이트 특성 하중해석을 위한 기상탑 바람 데이터 분석 및 풍력터빈 작용 하중 비교 평가 (Load Comparison Evaluation and Meteorological Mast Wind Data Analysis for Wind Turbine Site-specific Load Analysis)

  • 김성건;김범석
    • 풍력에너지저널
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    • 제13권3호
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    • pp.43-52
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    • 2022
  • Although wind turbines have obtained type certification according to international standards and are released to the market, they cannot be regarded as design evaluations that consider site characteristics. Therefore, it is necessary to study the site-specific load analysis method based on the meteorological data measured at the candidate site. In this study, site-specific load calculation was performed based on the meteorological data from the Jeju Haengwon mast. Analysis results were compared and analyzed with the results calculated by IEC design Class (IIA). For the fatigue loads at the blade root and tower base, the site-specific condition was lower than the IEC IIA, but in the case of the ultimate load, the site-specific condition showed higher results in some design load cases (DLCs). Selecting a wind turbine suitable for a site through load evaluation considering site conditions can prevent the reduction of operation and maintenance (O&M) costs and the power loss caused by downtime. Finally, it is expected to contribute to the project's levelized cost of energy (LCOE) reduction.

풍황 하중조건 데이터 자동생성화를 이용한 풍력터빈 하중해석의 효율 향상에 관한 연구 (Study on the efficiency improvement of wind turbine load analysis by using automatic generation for wind load condition data)

  • 안경민;임동수;이현주;최원호;이승구
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2006년도 추계학술대회
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    • pp.269-272
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    • 2006
  • Load analysis software enables to design wind turbines effectively and exactly. In this paper, Bladed software developed by Garrad Hassan and Partners is used for load analysis. When using Bladed software, many time is requested to input data which is called by pre-processing. So in this paper, pre-processing Is automated by in-house software(BX) With this BX software, we can reduce the total time for pre-processing about 90%.

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바람조건에 따른 1MW급 수평축 풍력터빈 브레이드의 하중 해석 (Aerodynamic Load Analysis for 1MW HAWT Blade According to IEC61400-1)

  • 김진;유기완;이창수
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2007년도 춘계학술대회
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    • pp.409-413
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    • 2007
  • To assure the structural integrity for the hub and low speed shaft (LSS) of the drive train, it is necessary to obtain the ultimate aerodynamic loads acting on the wind turbine blade. The aim of this study is to predict the time histories of 3 forces and 3 moments at the hub and the LSS based on the design load case of the IEC 61400-1. From the calculated results most of the load components have rotor revolution frequency whereas thrust and torque of the LSS show blade passage frequency. It turns out that the EWM wind condition involves the maximum ultimate loads at both hub and LSS of the horizontal axis wind turbine.

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풍력발전시스템의 블레이드에 작용하는 극한하중에 대한 난류의 영향 연구 (A Study on the Effects of Turbulence to Ultimate Loads Acting on the Blade of Wind Turbine)

  • 현승건;김건훈
    • 한국태양에너지학회 논문집
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    • 제33권1호
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    • pp.7-14
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    • 2013
  • This study has analysed the ultimate loads acting on a wind turbine which is operating in a high turbulent flow condition because the ultimate loads are critical factors on the safe design of wind turbine. Since wind flow on the most parts of Korean mountainous are strongly influenced by complex configurations of the topography, turbulence intensity on somewhere is so stronger than an international design standard. For this reason, the characteristics of turbulent wind data collected from actual sites were analyzed and used for the ultimate load evaluation of the wind turbine. With the 270 design load cases on the international standards, the differences of ultimate loads on the wind turbine operating in the standard or high turbulent wind condition are calculated and compared for the an enhanced knowledge of the safe design basis. As are result, it is revealed the specific ultimate loads are strongly affected by the high turbulent wind conditions, thus the characteristics of turbulent flow must be considered during the design of wind turbine.

판토그래프 가혹공력하중에 대한 연구 (Investigation on Severe Aerodynamic Load Condition about Pantograph)

  • 황재호;이동호;정경렬
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집E
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    • pp.361-366
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    • 2001
  • The present study describes a practical estimation procedure about the pantograph under several severe aerodynamic load conditions. As the operating speed of the Korean Train Express(KTX) reaches 350km/h, structural safety at various conditions should be examined at the design stage. In the present study, a compact and reliable procedure is developed to get aerodynamic loads on each part of the pantograph regarding the typhoon condition, the train/tunnel interaction, the train/train interaction and the side wind condition. In the estimation procedure, 3-dimensional steady and unsteady CFD simulation around the high speed train facilitates assigning the external local flow condition around the pantograph. The procedure is verified using the results of the low speed wind tunnel test at JARI and applied to 7 flow conditions and 4 operation configurations.

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Analysis of Dynamic Response Characteristics for 5 MW Jacket-type Fixed Offshore Wind Turbine

  • Kim, Jaewook;Heo, Sanghwan;Koo, WeonCheol
    • 한국해양공학회지
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    • 제35권5호
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    • pp.347-359
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    • 2021
  • This study aims to evaluate the dynamic responses of the jacket-type offshore wind turbine using FAST software (Fatigue, Aerodynamics, Structures, and Turbulence). A systematic series of simulation cases of a 5 MW jacket-type offshore wind turbine, including wind-only, wave-only, wind & wave load cases are conducted. The dynamic responses of the wind turbine structure are obtained, including the structure displacement, rotor speed, thrust force, nacelle acceleration, bending moment at the tower bottom, and shear force on the jacket leg. The calculated time-domain results are transformed to frequency domain results using FFT and the environmental load with more impact on each dynamic response is identified. It is confirmed that the dynamic displacements of the wind turbine are dominant in the wave frequency under the incident wave alone condition, and the rotor thrust, nacelle acceleration, and bending moment at the bottom of the tower exhibit high responses in the natural frequency band of the wind turbine. In the wind only condition, all responses except the vertical displacement of the wind turbine are dominant at three times the rotor rotation frequency (considering the number of blades) generated by the wind. In a combined external force with wind and waves, it was observed that the horizontal displacement is dominant by the wind load. Additionally, the bending moment on the tower base is highly affected by the wind. The shear force of the jacket leg is basically influenced by the wave loads, but it can be affected by both the wind and wave loads especially under the turbulent wind and irregular wave conditions.

Analysis of hurricane directionality effects using event-based simulation

  • Huang, Zhigang;Rosowsky, David V.
    • Wind and Structures
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    • 제3권3호
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    • pp.177-191
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    • 2000
  • This paper presents an approach for evaluating directionality effects for both wind speeds and wind loads in hurricane-prone regions. The focus of this study is on directional wind loads on low-rise structures. Using event-based simulation, hurricane directionality effects are determined for an open-terrain condition at various locations in the southeastern United States. The wind speed (or wind load) directionality factor, defined as the ratio of the N-year mean recurrence interval (MRI) wind speed (or wind load) in each direction to the non-directional N-year MRI wind speed (or wind load), is less than one but increases toward unity with increasing MRI. Thus, the degree of conservatism that results from neglecting directionality effects decreases with increasing MRI. It may be desirable to account for local exposure effects (siting effects such as shielding, orientation, etc.) in design. To account for these effects in a directionality adjustment, the factor described above for open terrain would need to be transformed to other terrains/exposures. A "local" directionality factor, therefore, must effectively combine these two adjustments (event directionality and siting or local exposure directionality). By also considering the direction-specific aerodynamic coefficient, a direction-dependent wind load can be evaluated. While the data necessary to make predictions of directional wind loads may not routinely be available in the case of low-rise structures, the concept is discussed and illustrated in this paper.

풍력 터빈 허브의 피로강도 평가 (Fatigue Strength Evaluation of Wind Turbine Hub)

  • 이현주;고장욱;오시덕
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 추계학술대회
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    • pp.1033-1038
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    • 2003
  • A wind turbine obtains its power input by converting the force of the wind into a torque (turning force) acting on the rotor blades. The amount of energy which the wind transfers to the rotor depends on the density of the air, the rotor area, and the wind speed. Because it has long term operating life and very complex load condition, the fatigue strength of each component must be considered. In this paper, we calculated the load condition by wind using a combined blade elemental theory and a FEM based analytical approach was use to evaluate the fatigue strength of a Hub of wind turbine. The effect of tensile mean stress was taken into account by the modified Goodman diagram. Using this approaches, we evaluated the fatigue strength of hub and main shaft and improved the design.

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