A comparison between the dynamics of horizontal and vertical axis offshore floating wind turbines

M. Borg, M. Collu

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)


The need to further exploit offshore wind resources in deeper waters has led to a re-emerging interest in vertical axis wind turbines (VAWTs) for floating foundation applications. However, there has been little effort to systematically compare VAWTs to the more conventional horizontal axis wind turbine (HAWT). This article initiates this comparison based on prime principles, focusing on the turbine aerodynamic forces and their impact on the floating wind turbine static and dynamic responses. VAWTs generate substantially different aerodynamic forces on the support structure, in particular, a potentially lower inclining moment and a substantially higher torque than HAWTs. Considering the static stability requirements, the advantages of a lower inclining moment, a lower wind turbine mass and a lower centre of gravity are illustrated, all of which are exploitable to have a less costly support structure. Floating VAWTs experience increased motion in the frequency range surrounding the turbine [number of blades] × [rotational speed] frequency. For very large VAWTs with slower rotational speeds, this frequency range may significantly overlap with the range of wave excitation forces. Quantitative considerations are undertaken comparing the reference NREL 5MW HAWT with the NOVA 5MWVAWT.

Original languageEnglish
Number of pages16
JournalPhilosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Issue number2035
Publication statusPublished - 28 Feb 2015


  • dynamics
  • floating wind turbines
  • horizontal axis wind turbine
  • offshore wind
  • renewable energy
  • vertical axis wind turbine


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