Wind Energy
Online ISSN : 1884-457X
Print ISSN : 0387-6217
ISSN-L : 0387-6217
Volume 39, Issue 1
Displaying 1-38 of 38 articles from this issue
  • Tomoaki UTSUNOMIYA, Iku SATO, Shigeo YOSHIDA, Takashi SHIRAISHI, Shige ...
    2015 Volume 39 Issue 1 Pages A_1-A_5
    Published: 2015
    Released on J-STAGE: September 30, 2016
    JOURNAL FREE ACCESS
    Dynamic response of a Floating Offshore Wind Turbine (FOWT) with Spar-type floating foundation is presented. The FOWT mounts a 100kW down-wind turbine, and is grid-connected. It was installed on June 11th, 2012 for the purpose of the demonstration experiment. During the experiment, the FOWT was attacked by Sanba (international designation: 1216), the strongest tropical typhoon worldwide in 2012. The central atmospheric pressure was 940 hPa when it was close to the FOWT, and the maximum significant wave height of 9.5m was recorded at the site. In this paper, the dynamic responses of the platform motion, the stresses at the tower sections and the chain tensions during the typhoon event, Sanba (1216), have been analyzed, and compared with the measured data.
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  • Takeshi ISHIHARA, Yuta TAKEI
    2015 Volume 39 Issue 1 Pages A_14-A_21
    Published: 2015
    Released on J-STAGE: September 30, 2016
    JOURNAL FREE ACCESS
    In this study, a new damping correction factor is proposed to provide accurate design response spectrum. Proposed response spectra show good agreement with those by time history analysis (THA) for both low and high damping ratio. The seismic load of wind turbine tower based on response spectrum method (RSM) is also presented and compared with those by THA. Torsional moment is calculated from acceleration at the top of tower evaluated by RSM and correction coefficient in the formula is proposed by systematic analysis. Moreover, seismic load at foundation is evaluated by Sway-Rocking (SR) model. The quantile value in response spectrum is determined as 0.85 to ensure the reliability level by the calibration with THA currently used for evaluations of seismic load on the wind turbine support structures. The seismic load predicted by RSM is verified by comparison with that by time history analysis.
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  • Takanori UCHIDA
    2015 Volume 39 Issue 1 Pages A_6-A_13
    Published: 2015
    Released on J-STAGE: September 30, 2016
    JOURNAL FREE ACCESS
    Because a significant portion of the topography in Japan is characterized by steep, complex terrain, which results in a complex spatial distribution of wind speed, great care is necessary for selecting a site for the construction of Wind Turbine Generators (WTGs). We have developed a Computational Fluid Dynamics (CFD) model for unsteady flow called Research Institute for Applied Mechanics, Kyushu University, COMputational Prediction of Airflow over Complex Terrain (RIAM-COMPACTR). The RIAM-COMPACTR CFD model is based on Large-Eddy Simulation (LES) technique. In this paper, the numerical wind simulation over the Taikoyama wind farm was executed using the high resolution elevation data. As a result, the numerical results obtained suggest that all the six WTGs in the Taikoyama wind farm are subject to significant influence from separated flow (terrain-induced turbulence) which is due to the topographical irregularity in front of WTGs. The new reproduction proposal was also done.
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