Effect of scouring in sand on monopile supported offshore wind turbines

K. A. Abhinav, Nilanjan Saha

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

This paper analyzes the influence of scour on the overall response of monopile-supported offshore wind turbines (OWTs) in 20-m water depth. Scouring effects on OWTs have been often studied within the geotechnical domain, considering static loads at the mudline. The present work attempts to address the
scour-induced problems in OWTs by making use of an integrated aerodynamic–hydrodynamic load approach in sandy soils. The OWT analysis is simulated for operational and shut-down (parked) condition. Under parked situations, the OWT blades are feathered, and power production is suspended, owing to
structural safety concerns. The 50 Monte Carlo responses of stochastic sea-state condition (wind speed with turbulence, significant wave height, and peak spectral period) are generated. Irregular, long-crested waves are generated using the Joint North Sea Wave Project (JONSWAP) spectrum. Then from each
simulation, the ensemble response is obtained. Sandy soils of varying densities are considered. Results indicate that OWTs founded on loose sands suffer significant stiffness (and hence natural frequency) reductions, shifting the structure into the resonance regime. Lateral responses also show an escalation
with reduction in density of sandy soil.
LanguageEnglish
Pages817-828
Number of pages12
JournalMarine Georesources & Geotechnology
Volume35
Issue number6
Early online date27 Dec 2016
DOIs
Publication statusPublished - 2017

Fingerprint

Offshore wind turbines
wind turbine
Sand
sand
sandy soil
Soils
Scour
significant wave height
sea state
scour
aerodynamics
effect
stiffness
Natural frequencies
Aerodynamics
water depth
Turbulence
Hydrodynamics
wind velocity
turbulence

Keywords

  • monopile
  • scouring

Cite this

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title = "Effect of scouring in sand on monopile supported offshore wind turbines",
abstract = "This paper analyzes the influence of scour on the overall response of monopile-supported offshore wind turbines (OWTs) in 20-m water depth. Scouring effects on OWTs have been often studied within the geotechnical domain, considering static loads at the mudline. The present work attempts to address thescour-induced problems in OWTs by making use of an integrated aerodynamic–hydrodynamic load approach in sandy soils. The OWT analysis is simulated for operational and shut-down (parked) condition. Under parked situations, the OWT blades are feathered, and power production is suspended, owing tostructural safety concerns. The 50 Monte Carlo responses of stochastic sea-state condition (wind speed with turbulence, significant wave height, and peak spectral period) are generated. Irregular, long-crested waves are generated using the Joint North Sea Wave Project (JONSWAP) spectrum. Then from eachsimulation, the ensemble response is obtained. Sandy soils of varying densities are considered. Results indicate that OWTs founded on loose sands suffer significant stiffness (and hence natural frequency) reductions, shifting the structure into the resonance regime. Lateral responses also show an escalationwith reduction in density of sandy soil.",
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Effect of scouring in sand on monopile supported offshore wind turbines. / Abhinav, K. A.; Saha, Nilanjan.

In: Marine Georesources & Geotechnology , Vol. 35, No. 6, 2017, p. 817-828.

Research output: Contribution to journalArticle

TY - JOUR

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AU - Saha, Nilanjan

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AB - This paper analyzes the influence of scour on the overall response of monopile-supported offshore wind turbines (OWTs) in 20-m water depth. Scouring effects on OWTs have been often studied within the geotechnical domain, considering static loads at the mudline. The present work attempts to address thescour-induced problems in OWTs by making use of an integrated aerodynamic–hydrodynamic load approach in sandy soils. The OWT analysis is simulated for operational and shut-down (parked) condition. Under parked situations, the OWT blades are feathered, and power production is suspended, owing tostructural safety concerns. The 50 Monte Carlo responses of stochastic sea-state condition (wind speed with turbulence, significant wave height, and peak spectral period) are generated. Irregular, long-crested waves are generated using the Joint North Sea Wave Project (JONSWAP) spectrum. Then from eachsimulation, the ensemble response is obtained. Sandy soils of varying densities are considered. Results indicate that OWTs founded on loose sands suffer significant stiffness (and hence natural frequency) reductions, shifting the structure into the resonance regime. Lateral responses also show an escalationwith reduction in density of sandy soil.

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