Semi-active vibration control of a semi-submersible offshore wind turbine using a tuned liquid multi-column damper

Fath, Alireza; Yazdi, Ehsan Azadi; Eghtesad, Mohammad

doi:10.1007/s40722-020-00171-x

Cited by 14 publications

(4 citation statements)

References 31 publications

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“…Platform motion may be reduced directly in semi-subs by allowing water to oscillate internally between floats as tuned mass dampers in resonance, e.g. Fath et al (2020), or by actively pumping between floats (Stansby 2021). The latter reduces motion by 30-50% by balancing heave-induced forces in floats with relatively small power requirements as the pumps can also operate as turbines, so the net power required has only to overcome friction losses in the connecting pipes.…”

Section: Introductionmentioning

confidence: 99%

A wind semi-sub platform with hinged floats for omnidirectional swell wave energy conversion

Stansby,

2024

J. Ocean Eng. Mar. Energy

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The capacity of wind turbines on offshore wind platforms is presently much greater than that for wave energy conversion. However, wind availability with speed greater than 5 m/s, just above cut in, is typically 30–40% requiring storage to provide uniformity of supply, but this may be improved by adding swell wave energy conversion with typical availability of 90%. A hybrid platform is considered with three effectively rigid cylindrical floats connected by beams at right angles to support a wind turbine with its base on the central float, and two wave energy floats, opposite the wind floats, with beams at 90° and hinges with dampers for mechanical energy absorption on the central float. With swell periods over 10 s, pitch resonance may be achieved with the fore and aft floats about half a wavelength apart with anti-phase forcing causing a moment on hinges above water level. The NREL 5 MW wind turbine is incorporated and average swell wave power absorption in a typical significant wave height of 2 m is over 200 kW. The analysis is by time domain linear diffraction–radiation modelling validated for other multi-float configurations. Significant wave energy conversion is omnidirectional over a wide range of heading angles. An added benefit is that in larger waves associated with strong winds, when the wave energy conversion would be disengaged, the wave float rotation on free hinges reduces the hub accelerations below that for rigid floats, enabling a longer time for wind power generation.

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Section: Introductionmentioning

confidence: 99%

A wind semi-sub platform with hinged floats for omnidirectional swell wave energy conversion

Stansby,

2024

J. Ocean Eng. Mar. Energy

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show abstract

“…Platform motion may be reduced directly in semi-subs by allowing water to oscillate between floats as tuned mass dampers in resonance, e.g. Fath et al (2020), or by actively pumping between floats (Stansby 2021). The latter reduces motion by 30-50% by balancing heave-induced forces in floats with relatively small power requirements as the pumps can also operate as turbines so the net power required has only to overcome friction losses in the connecting pipes.…”

Section: Introductionmentioning

confidence: 99%

A wind semi-sub platform with hinged floats for omnidirectional swell wave energy conversion

Stansby,

2023

Preprint

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The capacity of wind turbines on offshore wind platforms is presently much greater than that for wave energy conversion. However wind availability with speed greater than 5 m/s, just above cut in, is typically 30-40% requiring storage to provide uniformity of supply, but this may be improved by adding swell wave energy conversion with typical availability of 90%. A hybrid platform is considered with three effectively rigid cylindrical floats connected by beams at right angles to support a wind turbine with its base on the central float, and two wave energy floats, opposite the wind floats, with beams at 90o and hinges with dampers for mechanical energy absorption on the central float. With swell periods over 10 s pitch resonance may be achieved with the fore and aft floats about half a wavelength apart with anti-phase forcing causing a moment on hinges above water level. The NREL 5 MW wind turbine is incorporated and average swell wave power absorption in significant wave heights of 2 m is over 200 kW. The analysis is by time domain linear diffraction-radiation modelling validated for other multi-float configurations. Significant wave energy conversion is omnidirectional over a wide range of heading angles. An added benefit is that in larger waves associated with strong winds, when the wave energy conversion would be disengaged, the wave float rotation on free hinges reduces the hub accelerations below that for rigid floats, enabling a longer time for wind power generation.

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“…In this study, we propose a FVM-based liquid sloshing model in open access Computational Fluid Dynamics (CFD) software OpenFOAM by extending our in-house FNPF model for water wave problems (Lin et al, 2019;. To better simulate the sloshing flow excited by potentially six degree-of-freedom external motions, such as a tuned liquid multi-column damper in Fath et al (2020), the numerical model is constructed in the non-inertial coordinate system, which has the advantage of simplicity in dealing with body motions as well as implementing solid wall boundary conditions. In the following sections, the theory and governing equations for the FVM-based FNPF model are first described.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Liquid Sloshing Using a Fully Nonlinear Potential Flow Model in the Noninertial Coordinate System

Lin¹,

Qian²,

Bai³

2022

IJOPE

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Liquid sloshing has been one of the primary concerns in ocean and offshore engineering due to its significant effects on ship stability and structure integrity. To investigate sloshing flow problems, a 3-dimensional Finite Volume Method based Fully Nonlinear Potential Flow (FNPF) model in the non-inertial coordinate system is developed in the present study. In this model, the Laplace equation is spatially discretised and solved using a second-order accurate finite volume method from the open source computational fluid dynamics software OpenFOAM. For the fully nonlinear free surface problems, both kinematic and dynamic boundary conditions at the free surface are implemented in the mixed-Eulerian-Lagrangian (MEL) form to update the free surface elevation and velocity potential respectively. The FNPF sloshing model is validated against a number of available experimental measurements and numerical results for test cases under different external excitations. Finally, the conclusions in terms of model accuracy and applicability are summarised based on the validation and application results. It is found that the proposed FVM based sloshing FNPF model is able to simulate fully nonlinear liquid sloshing process in the non-inertial coordinate system.

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Semi-active vibration control of a semi-submersible offshore wind turbine using a tuned liquid multi-column damper

Cited by 14 publications

References 31 publications

A wind semi-sub platform with hinged floats for omnidirectional swell wave energy conversion

A wind semi-sub platform with hinged floats for omnidirectional swell wave energy conversion

A wind semi-sub platform with hinged floats for omnidirectional swell wave energy conversion

Numerical Simulation of Liquid Sloshing Using a Fully Nonlinear Potential Flow Model in the Noninertial Coordinate System

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