Modal dynamics and stability of large multi-megawatt deepwater offshore vertical-axis wind turbines: Initial support structure and rotor design impact studies Conference Paper uri icon

abstract

  • The availability of offshore wind resources in coastal regions, along with a high concentration of load centers in these areas, makes offshore wind energy an attractive opportunity for clean renewable electricity production. High infrastructure costs such as the offshore support structure and operation and maintenance costs for offshore wind technology, however, are significant obstacles that need to be overcome to make offshore wind a more cost-effective option. A vertical-axis wind turbine (VAWT) rotor configuration offers a potential transformative technology solution that significantly lowers cost of energy for offshore wind due to its inherent advantages for the offshore market. This paper presents an initial design impact study for assessing the dynamic stability of large multi-megawatt deepwater offshore VAWTs. The analysis and understanding of very large, highly flexible VAWT structures is further complicated by the rigid body modes of a floating support structure. A newly developed design tool for offshore VAWTs is employed to assess the stability of very large multi-megawatt VAWT configurations in a deepwater environment. To gain a fundamental understanding of tower resonance in VAWTs, an analytical expression for characterizing critical per-rev excitations for VAWT configurations is developed and presented. The influence of various support condition on structural modes of a VAWT is also investigated. For offshore deployment, a monopile support condition may exacerbate resonance concerns while floating platform supports may provide a means to alleviate resonance concerns. The effect of the large rotating structure on the rigid body modes of the turbine/platform system is also examined.

published proceedings

  • 32nd ASME Wind Energy Symposium

author list (cited authors)

  • Owens, B. C., Griffith, D. T., & Hurtado, J. E.

complete list of authors

  • Owens, BC||Griffith, DT||Hurtado, JE

publication date

  • February 2014