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Title: Effects of grit roughness and pitch oscillations on the S815 airfoil

Abstract

Horizontal axis wind turbine rotors experience unsteady aerodynamics due to wind shear when the rotor is yawed, when rotor blades pass through the support tower wake, and when the wind is gusting. An understanding of this unsteady behavior is necessary to assist in the calculation of rotor performance and loads. The rotors also experience performance degradation due to surface roughness. These surface irregularities are cause by the accumulation of insect debris, ice, and the aging process. Wind tunnel studies that examine both the steady and unsteady behavior of airfoils can help define pertinent flow phenomena, and the resultant data can be used to validate analytical computer codes. A S815 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory (OSU/AARL) 3 x 5 subsonic wind tunnel (3 x 5) under steady flow and stationary model conditions, as well as with the model undergoing pitch oscillations. To study the possible extent of performance loss due to surface roughness, a standard grit pattern (LEGR) was used to simulate leading edge contamination. After baseline cases were completed, the LEGR was applied for both steady state and model pitch oscillation cases. The Reynolds numbers used for steady state conditions weremore » 0.75, 1, 1.25, and 1.4 million, while the angle of attack ranged from {minus}20{degree} to +40{degree}. With the model undergoing pitch oscillations, data were acquired at Reynolds numbers of 0.75, 1, 1.25, and 1.4 million, at frequencies of 0.6, 1.2, and 1.8 Hz. Two sine wave forcing functions were used; {+-}5.5{degree} and {+-}10{degree}, at mean angles of attack of 8{degree}, 14{degree}, and 20{degree}. For purposes herein, any reference to unsteady conditions means that the model was in pitch oscillation about the quarter chord.« less

Authors:
; ;  [1]
  1. Ohio State Univ., Columbus, OH (United States)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States); The Ohio State Univ., Columbus, OH (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
266692
Report Number(s):
NREL/TP-442-7820
ON: DE96007942; CNN: Contract XF-1-11009-3; TRN: AHC29616%%89
DOE Contract Number:  
AC36-83CH10093
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Jul 1996
Country of Publication:
United States
Language:
English
Subject:
17 WIND ENERGY; HORIZONTAL AXIS TURBINES; AIRFOILS; PERFORMANCE TESTING; ROUGHNESS; FUNCTIONAL MODELS; TURBINE BLADES

Citation Formats

Reuss Ramsay, R, Hoffman, M J, and Gregorek, G M. Effects of grit roughness and pitch oscillations on the S815 airfoil. United States: N. p., 1996. Web. doi:10.2172/266692.
Reuss Ramsay, R, Hoffman, M J, & Gregorek, G M. Effects of grit roughness and pitch oscillations on the S815 airfoil. United States. https://doi.org/10.2172/266692
Reuss Ramsay, R, Hoffman, M J, and Gregorek, G M. 1996. "Effects of grit roughness and pitch oscillations on the S815 airfoil". United States. https://doi.org/10.2172/266692. https://www.osti.gov/servlets/purl/266692.
@article{osti_266692,
title = {Effects of grit roughness and pitch oscillations on the S815 airfoil},
author = {Reuss Ramsay, R and Hoffman, M J and Gregorek, G M},
abstractNote = {Horizontal axis wind turbine rotors experience unsteady aerodynamics due to wind shear when the rotor is yawed, when rotor blades pass through the support tower wake, and when the wind is gusting. An understanding of this unsteady behavior is necessary to assist in the calculation of rotor performance and loads. The rotors also experience performance degradation due to surface roughness. These surface irregularities are cause by the accumulation of insect debris, ice, and the aging process. Wind tunnel studies that examine both the steady and unsteady behavior of airfoils can help define pertinent flow phenomena, and the resultant data can be used to validate analytical computer codes. A S815 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory (OSU/AARL) 3 x 5 subsonic wind tunnel (3 x 5) under steady flow and stationary model conditions, as well as with the model undergoing pitch oscillations. To study the possible extent of performance loss due to surface roughness, a standard grit pattern (LEGR) was used to simulate leading edge contamination. After baseline cases were completed, the LEGR was applied for both steady state and model pitch oscillation cases. The Reynolds numbers used for steady state conditions were 0.75, 1, 1.25, and 1.4 million, while the angle of attack ranged from {minus}20{degree} to +40{degree}. With the model undergoing pitch oscillations, data were acquired at Reynolds numbers of 0.75, 1, 1.25, and 1.4 million, at frequencies of 0.6, 1.2, and 1.8 Hz. Two sine wave forcing functions were used; {+-}5.5{degree} and {+-}10{degree}, at mean angles of attack of 8{degree}, 14{degree}, and 20{degree}. For purposes herein, any reference to unsteady conditions means that the model was in pitch oscillation about the quarter chord.},
doi = {10.2172/266692},
url = {https://www.osti.gov/biblio/266692}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jul 01 00:00:00 EDT 1996},
month = {Mon Jul 01 00:00:00 EDT 1996}
}