Book Description
The effect on airfoil characteristics of surface roughness of varying degrees and types at different locations on an airfoil was investigated (at high values of the Reynolds number in the N.A.C.A. variable-density wind tunnel).
Author : Ray W. Hooker
Publisher :
Page : 10 pages
File Size : 27,95 MB
Release : 1933
Category : Aerofoils
ISBN :
The effect on airfoil characteristics of surface roughness of varying degrees and types at different locations on an airfoil was investigated (at high values of the Reynolds number in the N.A.C.A. variable-density wind tunnel).
Author : Nigel Gregory
Publisher :
Page : 33 pages
File Size : 45,65 MB
Release : 1973
Category : Aerodynamics
ISBN : 9780114705268
Author : Albert E. Von Doenhoff
Publisher :
Page : 24 pages
File Size : 46,29 MB
Release : 1944
Category : Aerodynamic load
ISBN :
Summary: Two low-drag airfoils, the NACA 747A315 and the NACA 747A415, designed to have reduced pitching moments about the quarter-chord point and moderately high values of the design lift coefficient have been tested in the NACA two-dimensional low-turbulence pressure tunnel. Section lift, drag, and pitching-moment coefficients are presented for Reynolds numbers of 3 x 106, 6 x 106, and 9 x 106, together with section lift and section drag data for a Reynolds number of 6 x 106 for the same airfoils with roughened leading edges.
Author : O. Schrenk
Publisher :
Page : 18 pages
File Size : 46,83 MB
Release : 1926
Category : Aerodynamics
ISBN :
The first group of a large series of contemplated experiments on the effect of roughness was intended to show the effect of great roughness on airfoils of various sizes and attitudes.
Author : Laurence K. Loftin
Publisher :
Page : 10 pages
File Size : 45,37 MB
Release : 1954
Category : Aerofoils
ISBN :
Information from the literature and from recent investigations is used herein to summarize briefly and effects of airfoil section parameters and flow variables on the aerodynamic characteristics of two-dimensional symmetrical airfoils at high angles of attack. The results presented indicate that airfoil thickness ratio, Reynolds number, Mach number, and surface roughness can all have an important effect on the maximum lift coefficient. The effect of surface roughness cause large decreases in maximum lift important. Not only can surface roughness cause large decreases in maximum lift coefficient, but also the magnitudes of the effects of Reynolds number, Mach number, and airfoil thickness ratio are much reduced by surface roughness. Beyond the stall, changes in section thickness ratio appear to have little effect on the aerodynamic characteristics of airfoil sections. An investigation of one section through an angle-of-attack range of from 0 to 360 degrees shows that the drag coefficient reaches a value of 2 at an angle of attack of 90 degrees.
Author : Frank T. Abbott
Publisher :
Page : 38 pages
File Size : 27,68 MB
Release : 1944
Category : Aerodynamics
ISBN :
In connection with studies of airfoils applicable to large high-speed aircraft, the effects of roughness on three 22-percent-thick airfoils were investigated. The tests were made over a range of Reynolds numbers from about 6,000,000 to 26,000,000 for the airfoils smooth and with roughness strips applied to the surfaces. The results indicated that for the roughened models the scale effect was generally favorable.
Author : Laurence K. Loftin
Publisher :
Page : 48 pages
File Size : 50,97 MB
Release : 1946
Category : Aerodynamic load
ISBN :
Summary: Tests were conducted with two typical low-drag airfoils of 90-inch chord to determine the effects of surface projections, grooves, and sanding scratches on boundary-layer transition. The Reynolds number at which a spanwise row of cylindrical projections would cause premature transition was determined for a range of Reynolds number from approximately 3 x 106 to 10 x 106. Data were obtained for projections of various sizes and chordwise locations on both low-drag airfoils. The results were analyzed on the assumption that the critical airfoil Reynolds number for a given projection was a function only of the local-flow conditions around the projection. This assumption neglected possible effects of tunnel turbulence, pressure gradient, boundary-layer Reynolds number, and the original extent of the laminar flow. The data correlated on the basis of this assumption within a range of critical airfoil Reynolds number of ±0.5 x 106 and within a range of projection height of ±0.002 inch. The tests of surface grooves and sanding scratches indicated that, for the range of Reynolds number investigated, the laminar boundary layer was much less sensitive to surface grooves and sanding scratches than to projections above the surface.
Author : Majid Delpassand
Publisher :
Page : 152 pages
File Size : 49,63 MB
Release : 1985
Category : Aerofoils
ISBN :
Author :
Publisher :
Page : 744 pages
File Size : 29,50 MB
Release :
Category : Aeronautics
ISBN :
Author : Chris C. Critzos
Publisher :
Page : 21 pages
File Size : 20,66 MB
Release : 1955
Category :
ISBN :