A comprehensive wind tunnel investigation into floating offshore wind turbine wake behavior has provided new insights into how platform motion affects downstream flow patterns. Researchers employed large-eddy simulations coupled with an actuator-line model to examine laboratory-scale turbine wakes under sinusoidal motions across five degrees of freedom: surge, sway, roll, pitch, and yaw.
The study employed an innovative measurement approach using radial probes that sampled circular cross-sections of the wake at multiple downstream positions, departing from traditional linear probe methods. Two motion scenarios were tested for each degree of freedom: low-frequency/high-amplitude and high-frequency/low-amplitude cases, representing distinct wake regimes.
Key findings revealed that low-frequency, high-amplitude motions produced wake behavior similar to fixed-bottom turbines, since these frequencies fall outside the dominant energy spectrum of naturally developing wakes. In contrast, high-frequency, low-amplitude oscillations—which coincide with the wake's peak energy frequencies—caused substantially amplified perturbations, irregular wake boundaries, and accelerated vortex trail expansion and merger.
High-frequency cases also exhibited sharper turbulence intensity peaks and faster overall wake recovery, with amplification concentrating at the tip and root vortex trails where shear instabilities are strongest. Notably, high-frequency surge motions presented an exception, slowing wake recovery at the prescribed frequency.
Despite the elevated blockage ratio inherent to wind tunnel testing, all observed phenomena aligned with established literature on full-scale floating offshore wind turbines. This validation confirms that fundamental wake dynamics are accurately captured in controlled laboratory environments, providing confidence for applying these results to industrial-scale floating offshore wind farms. The research demonstrates how platform motion characteristics significantly influence wake recovery and downstream turbine interactions—critical factors for optimizing power plant layouts and maximizing energy yield in floating wind installations.
