Roll motion mitigation of a barge-type floating wind turbine under random excitation using a tuned liquid column damper

ABSTRACT

This paper aims to numerically evaluate the performance of tuned liquid column damper (TLCD) on mitigating roll motion of a barge-type floating wind turbine system subjected to random excitation. The governing equations for modeling the interaction between the roll motion of the floating system and liquid sloshing in the TLCD were derived using a Lagrangian approach. Random excitation based on wave spectrum was generated to simulate applied moment. Then, under the constraints of barge dimension and vertical liquid column movement, Den Hartog’s method was used to obtain optimum TLCD parameters. The results show that the optimally designed TLCD can efficiently mitigate the roll motion of the floating wind turbine.

CO EDITOR-IN-CHIEF:

• Chen, Jeng-Tzong

ASSOCIATE EDITOR:

• Chen, Jeng-Tzong

KEYWORDS:

• Floating wind turbine
• tuned liquid column damper
• roll motion mitigation

Acknowledgments

The author wishes to acknowledge the financial aid via a research grant provided by the Ministry of Science and Technology and Bureau of Standards, Metrology & Inspection, M.O.E.A., Taiwan, R.O.C. [grant number MOST 109-2221-E-027-004].

Disclosure statement

No potential conflict of interest was reported by the author(s).

Nomenclature

A_harea of cross-section of horizontal column of a TLCD

A_varea of cross-section of vertical column of a TLCD

blength of horizontal liquid column in a TLCD

b_llength of a barge

b_wwidth of a barge

b_hheight of a barge

DMF_θdynamic magnification factor of rotational response of a floatingwind turbine system

dvertical distance between the waterline and the bottom of thebarge

Hdistance from water surface to the center line of the horizontalcolumn of a TLCD

H_ssignificant wave height

hlength of vertical liquid column in a TLCD

I_somoment of inertia of mass of a floating wind turbine system abouta rotational axis O

I_domoment of inertia of mass of fluid in a TLCD about a rotational axis O

m_smass of a floating wind turbine system

m_dmass of a TLCD

rratio of area of cross-section of vertical column to horizontal one

xdisplacement of horizontal liquid column of TLCD

ydisplacement of vertical liquid column of TLCD

βratio of forcing frequency to system natural frequency

δcoefficient of head loss of TLCD

γnon-dimensional peak shape parameter

λratio of sloshing frequency of liquid of TLCD to natural roll frequencyof floating system

μratio of mass moment of inertia of TLCD to floating wind turbinesystem about a rotational axis O

μ_mratio of mass of TLCD to floating wind turbine system

ωwave frequency

ω_fforcing frequency

ω_pangular spectral peak frequency

ω_dsloshing frequency of liquid in a TLCD

ω_snatural roll frequency of a floating wind turbine system

ρliquid density in a TLCD

σspectral width parameter

θrotation of a floating wind turbine system about a rotational axis O

ξ_dequivalent damping ratio

Additional information

Funding

This work was supported by the the Ministry of Science and Technology Taiwan, R.O.C. [MOST 109-2221-E-027-004].