Leading-Edge Roughness Effects on 63(3)-418 Airfoil Performance

White, Edward B.; Kutz, Douglas; Freels, Justin; Monschke, Jason; Grife, Ronald; Sun, Yang; Chao, David

doi:10.2514/6.2011-352

Cited by 17 publications

(28 citation statements)

References 7 publications

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“…White et al 2 completed this by testing a NACA 63 3 -418 with a clean, tripped, low-k, and high-k leading edge. The low-k and high-k leading edges had a maximum roughness height of 70 µm and 1.2 mm, respectively.…”

Section: Introductionmentioning

confidence: 98%

Realistic Leading-Edge Roughness Effects on Airfoil Performance

Maniaci

Rumsey

Ehrmann

et al. 2013

31st AIAA Applied Aerodynamics Conference

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Wind farm operators observe power production decay over time, with the exact cause unknown and difficult to quantify. A likely explanation is blade surface roughness, as wind turbines are continuously subjected to environmental hazards. Difficulty arises in understanding and quantifying performance degradation. Historically, wind turbine airfoil families were designed for the lift to be insensitive to roughness by simulating roughness with 2D trip strips. Despite this, roughness is still shown to negatively affect airfoil lift performance. Experiments have also illustrated that random-distributed roughness is not properly simulated by trip strips. Therefore, to better understand how real roughness effects performance, field measurements of turbine-blade roughness were made and simulated on an airfoil section in a wind tunnel. This data will serve to validate and calibrate a one-equation, computational roughness amplification model that interacts with the Langtry-Menter transition model. The observed roughness contains 2D steps, heavy 2D erosion, pitting, insects, and repairs. Of these observations, 2D steps from paint chips were characterized and recreated for this particular wind tunnel entry. The model was tested at chord Reynolds numbers up to 3.6 × 10 6 . Measurements of lift, drag, and pitching moment were made with and without roughness contamination. Transition location was acquired with infrared thermography and a hotfilm array. The paint roughness yields a consistent increase in drag compared to the clean configuration. Numerical simulations are only compared to the clean configuration and match well to lift, drag, and transition for Rec = 1.6 × 10 6 . However, drag is overpredicted at Rec = 3.2 × 10 6 .

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Section: Introductionmentioning

confidence: 98%

Realistic Leading-Edge Roughness Effects on Airfoil Performance

Maniaci

Rumsey

Ehrmann

et al. 2013

31st AIAA Applied Aerodynamics Conference

View full text Add to dashboard Cite

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“…Each harms performance by decreasing the section maximum lift and lift curve slope and increasing drag. 2 Erosion has been observed to result in 20% or greater loss in energy capture and can affect blades that have been operating for as little as three years. 3,4 Blade erosion has become a significant enough problem that 6% of all wind turbine related repairs are due to blade damage.…”

Section: Introductionmentioning

confidence: 99%

Influence of 2D Steps and Distributed Roughness on Transition on a NACA 63(3)-418

Ehrmann

White

2014

32nd ASME Wind Energy Symposium

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Wind farm operators observe power production decrease over time. Quantifying performance degradation on individual components is difficult, exacerbating the problem. One potential explanation is accumulation of blade surface roughness, as wind turbines are continuously subjected to environmental hazards. Historically, wind turbine airfoils were designed for lift to be insensitive to roughness by simulating roughness with 2D trip strips. However, roughness was still shown to negatively affect airfoil performance. Experiments have also illustrated that random-distributed roughness is not properly simulated by trip strips. To better understand how real-world roughness affects performance, field measurements of turbine-blade roughness were made and simulated on an airfoil section in a wind tunnel. Of the observed roughness types, insect roughness and paint chips were characterized and recreated as distributed roughness and a forward-facing step. Distributed roughness was tested in three heights and two density configurations. The model chord Reynolds number was varied between 0.8 to 4.4 × 10 6 . Measurements of lift, drag, and pitching moment were completed. Transition location was determined using both infrared thermography and hotfilm anemometry. Results indicate minimal performance loss due to paint-chip roughness. At Rec = 2.4 × 10 6 , L/Dmax decreased 40% for the dense 140 µm, sparse-extended 140 µm, and sparse 200 µm roughness. This indicates that both density and height are critical performance parameters. Lastly, all but one configuration had Rek,crit within predictions from literature.

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“…To simulate roughness, transition was forced at the leading-edge of the airfoils. Research conducted since this time has shown that forced transition models are unrepresentative of insect roughness [3] [16] [17]. Nevertheless, the NREL turbine blades showed vast improvements over the NACA and NASA blades in atmospheric tests.…”

Section: Ic Historical Airfoil Designmentioning

confidence: 99%

“…However, results from both airfoils are presented and compared. The role of airfoil thickness on roughness sensitivity is a key motivation of this work, so comparisons between the 18% thick NACA 63 3 King's Law can be related to the wire voltage to arrive at the following equation [43]:…”

Section: Iie Airfoil Selectionmentioning

confidence: 99%

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Roughness Sensitivity Comparisons of Wind Turbine Blade Sections

Wilcox

2017

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One explanation for wind turbine power degradation is insect roughness. Historical studies on insect-induced power degradation have used simulation methods which are either unrepresentative of actual insect roughness or too costly or time-consuming to be applied to wide-scale testing. Furthermore, the role of airfoil geometry in determining the relations between insect impingement locations and roughness sensitivity has not been studied.To link the effects of airfoil geometry, insect impingement locations, and roughness sensitivity, a simulation code was written to determine representative insect collection patterns for different airfoil shapes. Insect collection pattern data was then used to simulate roughness on an NREL S814 airfoil that was tested in a wind tunnel at Reynolds numbers between 1.6 × 10 6 and 4.0 × 10 6 . Results are compared to previous tests of a NACA 63 3 -418 airfoil.Increasing roughness height and density results in decreased maximum lift, lift curve slope, and lift-to-drag ratio. Increasing roughness height, density, or Reynolds number results in earlier bypass transition, with critical roughness Reynolds numbers lying within the historical range. Increased roughness sensitivity on the 25% thick NREL S814 is observed compared to the 18% thick NACA 63 3 -418.Blade-element-momentum analysis was used to calculate annual energy production losses of 4.9% and 6.8% for a NACA 63 3 -418 turbine and an NREL S814 turbine, respectively, operating with 200 µm roughness. These compare well to historical field measurements. iii ACKNOWLEDGEMENTS

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Leading-Edge Roughness Effects on 63(3)-418 Airfoil Performance

Cited by 17 publications

References 7 publications

Realistic Leading-Edge Roughness Effects on Airfoil Performance

Realistic Leading-Edge Roughness Effects on Airfoil Performance

Influence of 2D Steps and Distributed Roughness on Transition on a NACA 63(3)-418

Roughness Sensitivity Comparisons of Wind Turbine Blade Sections

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