Wind-tunnel test of the S814 thick root airfoil

Conference · Sun Jan 01 04:00:00 EST 1995

OSTI ID:27053

Somers, D M ^[1]; Tangler, J L ^[2]

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1. Airfoils, Inc., State College, VA (United States)
2. National Renewable Energy Lab., Golden, CO (United States)

The objective of this wind-tunnel test was to verify the predictions of the Eppler Airfoil Design and Analysis Code for a very thick airfoil having a high maximum lift coefficient (c{sub 1,max} designed to be largely insensitive to leading edge roughness effects. The 24-percent-thick S814 airfoil was designed with these characteristics to accommodate aerodynamic and structural considerations for the root region of a wind-turbine blade. In addition, the airfoil`s maximum lift-to-drag ratio was designed to occur it a high lift coefficient. To accomplish the objective, a two-dimensional wind-tunnel test of the S814 thick root airfog was conducted in January 1994 in the low-turbulence wind tunnel of the Delft University of Technology Low Speed Laboratory. Data were obtained for transition-free and transition-fixed conditions at Reynolds numbers of 0.7, 1.0, 1.5, 2.0, and 3.0 {times} 10{sup 6}. For the design Reynolds numbers of 1.5 {times} l0{sup 6}, the transition-free c{sub 1,max} is 1.3 which satisfies the design specification. However, this value is significantly lower than the predicted c{sub 1,max} of almost l.6. With transition-fixed at the is 1.2. The difference in c{sub 1,max} between the transition-free and transition-fixed conditions demonstrates the airfoil`s minimal sensitivity to roughness effects. The S814 root airfoil was designed to complement existing NREL low c{sub 1,max} tip-region airfoils for rotor blades 10 to 15 meters in length.

• Research Organization: National Renewable Energy Lab., Golden, CO (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC36-83CH10093
• OSTI ID: 27053
• Report Number(s): NREL/TP--442-7388; CONF-950116--7; ON: DE95000268
• Country of Publication: United States
• Language: English

Related Subjects

17 WIND ENERGY
AERODYNAMICS
AIRFOILS
HORIZONTAL AXIS TURBINES
REYNOLDS NUMBER
TESTING
TURBINE BLADES
WIND TUNNELS