Probabilistic analysis of wind turbine performance degradation due to blade erosion accounting for uncertainty of damage geometry

Assessing the Progression of Wind Turbine Energy Yield Losses Due to Blade Erosion by Resolving Damage Geometries from Lab Tests and Field Observations

“…This impairs the airfoil overall performance over most positive AoAs, as visible in Fig. 10 and discussed further in [7,22]. This loss dominates over those of modeled or resolved smoother roughness, highlighting the strong dependence of the turbine performance reduction on the geometric characteristics of the larger resolved scales of erosion, which depend also on the LE material properties.…”

“…An extensive study of the sensitivity of LEE-induced AEP losses to mean wind speed and turbulence intensity is reported in [5]. The sensitivity analyses of [7] also indicate that the AEP loss increase due to higher turbulence intensity at the onshore site may be comparable with that due to lower mean wind speed.…”

“…7 reports the mean profiles TI(𝑉 ) at the offshore and onshore sites. The notable TI level difference of the two sites has a significant weight on the difference between offshore and onshore AEP of a given turbine [7].…”

“…The AEP loss due to LEE is difficult to measure, partly because it depends on the detailed geometry of the eroded surface. To date, the actual value of AEP lost to LEE is uncertain, with recently reported estimates for wind farms ranging from 0.5 to 8% [3][4][5][6][7]. The large scatter of the reported AEP losses is partly due to the fact that this quantity depends on the specific geometry of the blade surface perturbation As erosion progresses and the perturbations of the LE geometry approach or exceed the BL thickness, additional aerodynamic losses occur, which may vary significantly with the specific LEE damage [15].…”

“…The large scatter of the reported AEP losses is partly due to the fact that this quantity depends on the specific geometry of the blade surface perturbation As erosion progresses and the perturbations of the LE geometry approach or exceed the BL thickness, additional aerodynamic losses occur, which may vary significantly with the specific LEE damage [15]. These phenomena contribute, with strength depending on the erosion severity, to premature separation of the BL on the airfoil upper side at AoAs where the nominal airfoil has a clean flow [7,16,17], with consequent reduction of the lift and further increase of the drag.…”