2026 Bourhis Wind Turbine Wake Dissipation

The dissipation of turbulent kinetic energy (TKE) is experimentally investigated in the wake of a diameter D=0.58 m wind turbine subjected to various intensities of high-Reynolds-number free-stream turbulence (FST) generated by an active turbulence-producing grid. The study identifies an annular region of increased normalized dissipation, C ε, in the outer wake for low- and moderate-intensity FST, coinciding with intensified turbulence intermittency at both small and large scales. In the blade-tip region, C ε scales with √Re D/Re λ, indicating a non-equilibrium dissipation regime associated with the inter-scale energy flux of TKE in the energy cascade's inertial range. In contrast, at the wake centerline, C ε remains relatively constant with increasing streamwise distance, suggesting either classical equilibrium turbulence or a balanced non-equilibrium condition, with small-scale intermittency. Under high-intensity FST conditions, the large-scale intermittency diminishes, corresponding with the disruption of tip-vortex structures, and no single turbulent Reynolds number scaling for C ε was identified, as multiple intense turbulence streams were present.