2026 de Oliveira Wake Induced Blade Dynamics

Wind turbines operating downstream of others in a farm are routinely exposed to wake-induced inflow, which results in reduced mean velocity and elevated turbulence, ultimately driving power deficits and additional structural fatigue. This study aims to enhance understanding of the direct effects of wakes on blade-level structural loading, which has been under-explored experimentally due to the sparse spatial coverage of conventional point-based strain sensors. We conduct a wind-tunnel experiment using two 1 m-diameter turbine models, where one blade of the downstream turbine (WT2) is equipped with distributed Rayleigh-backscattering fibre-optic strain sensors to obtain spatially continuous strain measurements across the blade span. By varying the relative position of the upstream turbine (WT1) to the downstream turbine (WT2), we map power output, spanwise strain, and accumulated fatigue-relevant loading across the wake profile. Our results demonstrate that full wake impingement leads to blade loading suppression due to velocity deficits, whereas partial wake overlap generates substantial load intermittency and higher relative fatigue-relevant loading, presenting a less favourable trade-off between energy yield and structural loading. This indicates that minimizing partial-wake exposure should be prioritized in wind-farm design and turbine spacing.