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Research on the Fundamental Understanding of the Behavior of a Very Large Floating Structure in Waves

Research Project

Project/Area Number 12650907
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 海洋工学
Research InstitutionOsaka University

Principal Investigator

TAKAGI Ken  Osaka University, Naval Arch. & Ocean Eng. Assoc. Prof., 大学院・工学研究科, 助教授 (90183433)

Project Period (FY) 2000 – 2002
Project Status Completed (Fiscal Year 2002)
Budget Amount *help
¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2002: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2001: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2000: ¥1,300,000 (Direct Cost: ¥1,300,000)
KeywordsMega-Float / Mat Type VLFS / Ray Method / Integral Equation / Hydro-elasticity / Zero-draft Approximation / Parabolic Approximation / Corner Problem / 漂流モーメント / 漂流力 / 境界積分方程式 / WKBJ近似 / 放物近似
Research Abstract

A concept of Very Large Floating Structure (VLFS) has been offered at the Mega-Float project in Japan that has a mat-like thin configuration while the horizontal scale is very large. They developed several computer codes to estimate the motion of VLFS, however the code is too time consuming and is not useful for the conceptual design. In order to solve this problem, the present study has started form formulating an integral equation which represents the hydro-elastic behavior of a VLFS in waves. Following results of the investigation of the integral equation, an application of the ray theory to hydro-elastic behavior of VLFS has been proposed. The theory itself is based on the classical ray theory, in which we used the fact that the hydro-elastic motion of VLFS can be regarded as wave propagation in the platform, and employed an assumption that the wavelength is very short compared with the horizontal size of VLFS. The classical ray theory insists that the wave field in and around the platform is represented as a summation of wave rays. The ray theory has been improved on two points. The shortcoming of the conventional ray theory is that the wave amplitude is suddenly changed along a ray that passes through a corner. This shortcoming is overcome by applying the parabolic approximation. The second improvement is that they extended the computer code to be applicable for arbitrary bottom, environmental and body geometry. Using this method, we demonstrated the influence of bottom topology and the influence of non-uniform rigidity of the structure and several interesting shapes of the structure have been offered to make motion of VLFS smaller. In order to demonstrate the accuracy of the present approach to the estimation of hydro-elastic behavior of VLFS, experiments in a small wave tank with a micro scale model has been also carried out. The ray method has been validated with experimental results.

Report

(4 results)
  • 2002 Annual Research Report   Final Research Report Summary
  • 2001 Annual Research Report
  • 2000 Annual Research Report
  • Research Products

    (28 results)

All Other

All Publications (28 results)

  • [Publications] Takagi, K., Yano, W., Nagayasu, M.: "Wave Drift Force and Moment Acting on a Very Large Floating Structure of Arbitrary Geometry"Proceedings of The Twelfth International Offshore and Polar Engineering Conference Kitakyushu, Japan. 1. 358-364 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K., Nagayasu, M.: "Simulation of the Hydro-elastic Behavior of a Mat-type Very Large Floating Structure"Proc. of Int. Symposium on Modeling and their Application IA'02, Osaka. 175-180 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K., Nagayasu, M., Yano, W.: "Estimation of Hydroelastic Behavior of a Mat-Type Very Large Floating Structure by the Ray Method"Proc. Int. Symposium on Ocean Space Utilization Technology, Tokyo. 68-74 (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K.: "Hydroelastic response of a very large floating structure in waves -a simple representation by the parabolic approximation"Applied Ocean Research. 24. 175-183 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K: "Parabolic Approximation of the Hydro-elastic Behavior of a Very Large Floating Structure in Oblique Waves"Proc. of 16th Int. Workshop on Water Waves and Floating Bodies, Hiroshima. 1. 153-156 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K., Nagayasu, M.: "Hydroelastic Behavior of a Mat-Type Very Large Floating Structure of Arbitrary Geometry"Proc. of Oceans 2002, Honolulu. 2. 1923-1929 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K.: "Quarter Plane Problem of a Floating Elastic Plate"J Engineering Mathematics. (submitted).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K: "A Theoretical Approach to the Slamming Impact Pressure Acting on the VLFS"Int. J. of Offshore and Polar Engineering. Vol.12 No.1. 10-15 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K., Kohara, K.: "Application of the Ray-Theory to Hydro-Elastic Behavior of VLFS"Proc. of 10th Int. Offshore and Polar Eng. Conference. 1. 72-77 (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] 高木 健: "VLFSの波浪中弾性挙動と漂流力に対するWKBJ近似の応用"関西造船協会誌. 第234号. 79-84 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K.: "Application of WKBJ approximation to Hydro-Elastic Behavior and Drift Force of VLFS"J. of Kansai Soc. of Naval Architects, Japan. Vol.234. 79-84 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K. and Kohara, K.: "Application of the Ray-Theory to Hydro-Elastic Behavior of VLFS"Proc. of 10th Int. Offshore and Polar Eng. Conference, Sheattle. 72-77 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K.: "Parabolic Approximation of the Hydro-elastic Behavior of a Very Large Floating Structure in Oblique Waves"Proc. of 16th Int. Workshop on Water Waves and Floating Bodies, Hiroshima. 153-156 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K. and Nagayasu, M.: "Hydroelastic Behavior of a Mat-Type Very Large Floating Structure of Arbitrary Geometry"Proc. of Oceans 2001, Honolulu. Vol.2. 1923-1929 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K., Yano, W. and Nagayasu, M.: "Wave Drift Force and Moment Acting on a Very Large Floating Structure of Arbitrary Geometry"Proceedings of The Twelfth International Offshore and Polar Engineering Conference Kitakyushu, Japan. 358-364 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K. and Nagayasu, M.: "Simulation of the Hydro-elastic Behavior of a Mat-type Very Large Floating Structure"Proc. of Int. Symposium on Modeling and their Application IA'02, Osaka. 175-180 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K.: "A Theoretical Approach to the Slamming Impact Pressure Acting on the VLFS"Int. J. of Offshore and Polar Engineering. Vol.12, No.1. 10-15 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K.: "Hydroelastic response of a very large floating structure in waves - a simple representation by the parabolic approximation"Applied Ocean Research. Vol.24. 175-183 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K., Nagayasu, M. and Yano, W.: "Estimation of Hydroelastic Behavior of a Mat-Type Very Large Floating Structure by the Ray Method"Proc. Int. Symposium on Ocean Space Utilization Technology, Tokyo. 68-74 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K.: "Quarter Plane Problem of a Floating Elastic Plate"submitted to the J Engineering Mathematics.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Takagi, K., Yano, W., Nagayasu, M.: "Wave Drift Force and Moment Acting on a Very Large Floating Structure of Arbitrary Geometry"Proceedings of The Twelfth International Offshore and Polar Engineering Conference Kitakyushu, Japan. 1. 358-364 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] Takagi, K., Nagayasu, M.: "Simulation of the Hydro-elastic Behavior of a Mat-type Very Large Floating Structure"Proc. of Int. Symposium on Modeling and their Application IA'02, Osaka. 175-180 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] Takagi, K., Nagayasu, M., Yano, W: "Estimation of Hydroelastic Behavior of a Mat-Type Very Large Floating Structure by the Ray Method"Proc. Int. Symposium on Ocean Space Utilization Technology, Tokyo. 68-74 (2003)

    • Related Report
      2002 Annual Research Report
  • [Publications] Takagi, K.: "Hydroelastic response of a very large floating structure in waves -a simple representation by the parabolic approximationpp"Applied Ocean Research. 24. 175-183 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] Takagi, K: "Parablic Approximation of the Hydro-elastic Behavior of a Very Large Floating Structure in Oblique Waves"Proc. of 16th Int. Workshop on Water Waves and Floating Bodies, Hiroshima. 1. 153-156 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] Takagi, K., Nagayasu, M.: "Hydroelastic Behavior of a Mat-Type Very Large Floating Structure of Arbitrary Geometry"Proc. of Oceans 2002, Honolulu. 2. 1923-1929 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] Takagi,K.and Kohara,K.: "Application of the Ray-Theory to Hydro-Elastic Behavior of VLFS"Proc.of 10th Int.Offshore and Polar Eng.Conference. 72-77 (2000)

    • Related Report
      2000 Annual Research Report
  • [Publications] 高木健: "VLFSの波浪中弾性挙動と漂流力に対するWKBJ近似の応用、、第234号"関西造船協会誌. 234. 79-84 (2000)

    • Related Report
      2000 Annual Research Report

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Published: 2000-04-01   Modified: 2016-04-21  

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