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An experimental low Reynolds number comparison of a Wortmann FX67-K170 airfoil, a NACA 0012 airfoil and a NACA 64-210 airfoil in simulated heavy rainWind tunnel experiments were conducted on Wortmann FX67-K170, NACA 0012, and NACA 64-210 airfoils at rain rates of 1000 mm/hr and Reynolds numbers of 310,000 to compare the aerodynamic performance degradation of the airfoils and to attempt to identify the various mechanisms which affect performance in heavy rain conditions. Lift and drag were measured in dry and wet conditions, a variety of flow visualization techniques were employed, and a computational code which predicted airfoil boundary layer behavior was used. At low angles of attack, the lift degradation in wet conditions varied significantly between the airfoils. The Wortmann section had the greatest overall lift degradation and the NACA 64-210 airfoil had the smallest. At high angles of attack, the NACA 64-210 and 0012 airfoils had improved aerodynamic performance in rain conditions due to an apparent reduction of the boundry layer separation. Performance degradation in heavy rain for all three airfoils at low angles of attack could be emulated by forced boundary layer transition near the leading edge. The secondary effect occurs at time scales consistent with top surface water runback times. The runback layer is thought to effectively alter the airfoil geometry. The severity of the performance degradation for the airfoils varied. The relative differences appeared to be related to the susceptibility of each airfoil to premature boundary layer transition.
Document ID
19870016564
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Craig, Anthony P.
(Massachusetts Inst. of Tech. Cambridge, MA, United States)
Hansman, R. John
(Massachusetts Inst. of Tech. Cambridge, MA, United States)
Date Acquired
September 5, 2013
Publication Date
June 1, 1987
Subject Category
Aerodynamics
Report/Patent Number
NAS 1.26:181119
ASL-87-1
NASA-CR-181119
Accession Number
87N25997
Funding Number(s)
CONTRACT_GRANT: NAG1-568
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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