Brief communication: A novel wake mixing phenomenon and key parameters for wake recovery of floating wind turbines subjected to surge motions

Abstract

This letter clarifies the key parameters governing the wake recovery of a floating wind turbine undergoing surge motions. A dedicated wind tunnel campaign covering reduced frequencies ( St p ) well beyond the current literature is presented. This enabled a full characterisation of the wake recovery and the discovery of a previously unreported wake mixing phenomenon. We highlight three main findings: (i) enhanced wake recovery of the surging turbine is highly sensitive to thrust, (ii) wake recovery is characterised by the ratio of motion velocity amplitude to wind speed and St p , and (iii) a previously unreported flow phenomenon improves wake recovery when the motion frequency is slightly lower than the blade passing frequency.