Bottom Slamming on Heaving Point Absorber Wave Energy Devices

Griet De Backer, Marc Vantorre, Peter Frigaard, Charlotte Beels, Julien De Rouck

Research output: Contribution to journalJournal articleResearchpeer-review

9 Citations (Scopus)

Abstract

Oscillating point absorber buoys may rise out of the water and be subjected to bottom slamming upon re-entering the water. Numerical simulations are performed to estimate the power absorption, the impact velocities and the corresponding slamming forces for various slamming constraints. Three buoy shapes are considered: a hemisphere and two conical shapes with deadrise angles of 30 and 45, with a waterline diameter of 5 m. The simulations indicate that the risk of rising out of the water is largely dependent on the buoy draft and sea state. Although associated with power losses, emergence occurrence probabilities can be significantly reduced by adapting the control parameters. The magnitude of the slamming load is severely influenced by the buoy shape. The ratio between the peak impact load on the hemisphere and that on the 45 cone is approximately 2, whereas the power absorption is only 4-8% higher for the 45 degrees cone. This work illustrates the need to include slamming considerations aside from power absorption criteria in the buoy shape design process and the control strategy.
Original languageEnglish
JournalJournal of Marine Science and Technology
Volume15
Issue number2
Pages (from-to)119-130
Number of pages21
ISSN0948-4280
DOIs
Publication statusPublished - 2010

Keywords

  • Emergence occurrence probability
  • Impact
  • Point absorber
  • Slamming
  • Wave energy

Cite this

De Backer, Griet ; Vantorre, Marc ; Frigaard, Peter ; Beels, Charlotte ; De Rouck, Julien. / Bottom Slamming on Heaving Point Absorber Wave Energy Devices. In: Journal of Marine Science and Technology. 2010 ; Vol. 15, No. 2. pp. 119-130.
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title = "Bottom Slamming on Heaving Point Absorber Wave Energy Devices",
abstract = "Oscillating point absorber buoys may rise out of the water and be subjected to bottom slamming upon re-entering the water. Numerical simulations are performed to estimate the power absorption, the impact velocities and the corresponding slamming forces for various slamming constraints. Three buoy shapes are considered: a hemisphere and two conical shapes with deadrise angles of 30 and 45, with a waterline diameter of 5 m. The simulations indicate that the risk of rising out of the water is largely dependent on the buoy draft and sea state. Although associated with power losses, emergence occurrence probabilities can be significantly reduced by adapting the control parameters. The magnitude of the slamming load is severely influenced by the buoy shape. The ratio between the peak impact load on the hemisphere and that on the 45 cone is approximately 2, whereas the power absorption is only 4-8{\%} higher for the 45 degrees cone. This work illustrates the need to include slamming considerations aside from power absorption criteria in the buoy shape design process and the control strategy.",
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Bottom Slamming on Heaving Point Absorber Wave Energy Devices. / De Backer, Griet; Vantorre, Marc; Frigaard, Peter; Beels, Charlotte; De Rouck, Julien.

In: Journal of Marine Science and Technology, Vol. 15, No. 2, 2010, p. 119-130.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Bottom Slamming on Heaving Point Absorber Wave Energy Devices

AU - De Backer, Griet

AU - Vantorre, Marc

AU - Frigaard, Peter

AU - Beels, Charlotte

AU - De Rouck, Julien

PY - 2010

Y1 - 2010

N2 - Oscillating point absorber buoys may rise out of the water and be subjected to bottom slamming upon re-entering the water. Numerical simulations are performed to estimate the power absorption, the impact velocities and the corresponding slamming forces for various slamming constraints. Three buoy shapes are considered: a hemisphere and two conical shapes with deadrise angles of 30 and 45, with a waterline diameter of 5 m. The simulations indicate that the risk of rising out of the water is largely dependent on the buoy draft and sea state. Although associated with power losses, emergence occurrence probabilities can be significantly reduced by adapting the control parameters. The magnitude of the slamming load is severely influenced by the buoy shape. The ratio between the peak impact load on the hemisphere and that on the 45 cone is approximately 2, whereas the power absorption is only 4-8% higher for the 45 degrees cone. This work illustrates the need to include slamming considerations aside from power absorption criteria in the buoy shape design process and the control strategy.

AB - Oscillating point absorber buoys may rise out of the water and be subjected to bottom slamming upon re-entering the water. Numerical simulations are performed to estimate the power absorption, the impact velocities and the corresponding slamming forces for various slamming constraints. Three buoy shapes are considered: a hemisphere and two conical shapes with deadrise angles of 30 and 45, with a waterline diameter of 5 m. The simulations indicate that the risk of rising out of the water is largely dependent on the buoy draft and sea state. Although associated with power losses, emergence occurrence probabilities can be significantly reduced by adapting the control parameters. The magnitude of the slamming load is severely influenced by the buoy shape. The ratio between the peak impact load on the hemisphere and that on the 45 cone is approximately 2, whereas the power absorption is only 4-8% higher for the 45 degrees cone. This work illustrates the need to include slamming considerations aside from power absorption criteria in the buoy shape design process and the control strategy.

KW - Emergence occurrence probability

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KW - Point absorber

KW - Slamming

KW - Wave energy

KW - Emergence occurrence probability

KW - Impact

KW - Point absorber

KW - Slamming

KW - Wave energy

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DO - 10.1007/s00773-010-0083-0

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JO - Journal of Marine Science and Technology

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