Lift of a Rotating Circular Cylinder in Unsteady Flows

摘要

A cylinder rotating in steady current experiences a lift known as theMagnus effect. In the present study the effect of waves on the Magnuseffect has been investigated. This situation is experienced with thenovel floating offshore vertical axis wind turbine (VAWT) conceptcalled the DEEPWIND concept, which incorporates a rotating sparbuoy and thereby utilizes seawater as a roller-bearing. The a prioriassumption and the results suggest that the lift in waves, to a firstapproximation, may be represented by a formulation similar to thewell-known Morison formulation. The force coefficients areexperimentally found to primarily depend on the ratio between thesurface speed of the cylinder and the outer flow velocity.