A Scale and Turbulence Effects on the Lift and Drag Characteristics of the NACA 653-418 PDF Download

Author: John H. Quinn
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 40

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Book Description
Summary: An investigation in two NACA wind tunnels has determined the effect of Reynolds number and stream turbulence on the lift and drag characteristics of a low-drag airfoil, the NACA 653-418, a=1.0 section, particularly at low Reynolds numbers, to give an indication of the performance of low-drag wings in low-scale tests. The results are correlated with similar data for the same airfoil section in the NACA two-dimensional low-turbulence pressure tunnel to provide data over a range of Reynolds number from 0.19 to 9.0 x 106. Large increases in minimum drag coefficient were found as the Reynolds number decreased. This effect was particularly marked at Reynolds numbers below 1.5 x 106. At Reynolds numbers below 1.5 x 106, stream turbulence had little effect on the drag characteristics of the NACA 653-418 airfoil section when compared on the basis of test Reynolds number but, at higher Reynolds numbers, stream turbulence had a detrimental effect on drag. Large decreases in maximum lift coefficient were found with decreasing Reynolds number; most of this decrease was encountered at Reynolds numbers above 2.0 x 106. Marked differences in maximum lift were apparent between the results obtained at high and low turbulence. When compared on the basis of effective Reynolds number, however, fair agreement was reached between the data obtained under both turbulence conditions.