Download or read book Effects of Airfoil Thickness and Maximum Lift Coefficient on Roughness Sensitivity written by and published by . This book was released on 2005 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: A matrix of airfoils has been developed to determine the effects of airfoil thickness and the maximum lift to leading-edge roughness. The matrix consists of three natural-laminar-flow airfoils, the S901, S902, and S903, for wind turbine applications. The airfoils have been designed and analyzed theoretically and verified experimentally in the Pennsylvania State University low-speed, low-turbulence wind tunnel. The effect of roughness on the maximum life increases with increasing airfoil thickness and decreases slightly with increasing maximum lift. Comparisons of the theoretical and experimental results generally show good agreement.

Download or read book Effects of Airfoil Thickness and Maximum Lift Coefficient on Roughness Sensitivity written by Dan M. Somers and published by . This book was released on 2005 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effects of Roughness at High Reynolds Numbers on the Lift and Drag Characteristics of Three Thick Airfoils written by Frank T. Abbott and published by . This book was released on 1944 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Airfoil Section Characteristics at High Angles of Attack written by Laurence K. Loftin and published by . This book was released on 1954 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Effects of Specific Types of Surface Roughness on Boundary layer Transition written by Laurence K. Loftin and published by . This book was released on 1946 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Effects of Thickness on the Aerodynamic Characteristics of an Initial Low speed Family of Airfoils for General Aviation Applications written by Robert J. McGhee and published by . This book was released on 1976 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Summary of Low Speed Airfoil Data written by Michael S. Selig and published by Soartech. This book was released on 1995 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Mach Number Up to 0 34 and Reynolds Number Up to 8 000 000 on the Maximum Lift Coefficient of a Wing of NACA 66 series Airfoil Sections written by G. Chester Furlong and published by . This book was released on 1950 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of Mach numbers up to 0.34 and Reynolds number up to 8,000,000 on the maximum lift coefficient of the wing of NACA 66-weries airfoil sections are presented. The wing was tested with full-span and partial-span split flaps deflected 60 degrees and without flaps. The results indicated that the peak values of maximum lift coefficient occurred at free-stream Mach numbers of approximately 0.212 and 0.227 for the flaps-retracted configuration and 0.138 and 0.196 for the full-span flaps-deflected configuration for tunnel pressures of 33 and 14.7 pounds per square inch, respectively.

Download or read book Effect of Thickness Camber and Thickness Distribution on Airfoil Characteristics at Mach Numbers Up to 1 0 written by Bernard N. Daley and published by . This book was released on 1952 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Compressibility on Maximum Lift Coefficients for Six Propeller Airfoils written by Harold E. Cleary and published by . This book was released on 1945 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: An extension of previously reported data on the variation of lift coefficient with Mach number, camber, and thickness ratio is presented. The data were obtained from pressure-distribution tests in the Langley 8-foot high-speed tunnel of six propeller airfoils of 1-foot chord.

Download or read book The Influence of Two dimensional Stream Shear on Airfoil Maximum Lift written by Robert J. Vidal and published by . This book was released on 1961 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of stre m v locity gradient on airfoil maximum lift are defined with experiment l da a ob ained in a simulated two-dimensional slipstream. The experime t l results show that w en po itioned near the slips ream plane of symmetry, the airfoil m ximum lift vari s markedly with location in the slipstream. In movi g he irfoil from abov to below the slipstream plane of symmetry through a total distance corresponding to the airfoil thickne s, force data and boundary-lay r observations show that boundary-layer separation is delayed to higher angle of a ck, a d the airfoil maximum lift is doubled. It is concluded that the destalling effect ob erved in t nonu ifor lipstream is o associated wit slipstream bou ry interferenc but stems from the influence of e large local slipstream shear on airfoil characteristics The effects of uniform no uniform shear on airfoil lift and pres ure dis ribution are discussed, within the framework of existing first-order, small-shear theory, to show that t ese effects of shear tend to promote stall. A Pohlhausen calculation of th laminary boundary layer in a stream with s ar is used to identify an to as ess the eff cts of stream shear on boundary-layer separation criteria.

Download or read book Wind tunnel Results for an Improved 21 percent thick Low speed Airfoil Section written by and published by . This book was released on 1978 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Low speed Aerodynamic Characteristics of a 17 percent thick Medium Speed Airfoil Designed for General Aviation Applications written by Robert J. McGhee and published by . This book was released on 1980 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind tunnel tests were conducted to determine the low speed two dimensional aerodynamic characteristics of a 17 percent thick medium speed airfoil (MS(1)-0317) designed for general aviation applications. The results were compared with data for the 17 percent thick low speed airfoil (LS(1)-0417) and the 13 percent thick medium speed airfoil (MS(1)-0313). Theoretical predictions of the drag rise characteristics of this airfoil are also provided. The tests were conducted in the Langley low turbulence pressure tunnel over a Mach number range from 0.10 to 0.32, a chord Reynolds number range from 2 million to 12 million, and an angle of attack range from about -8 to 20 deg.

Download or read book Technical Note National Advisory Committee for Aeronautics written by United States. National Advisory Committee for Aeronautics and published by . This book was released on 1948 with total page 936 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Surface Roughness and Vortex Generators on the LS 1 0417MOD Airfoil written by and published by . This book was released on 1995 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: An 18-inch constant-chord model of the LS(l)-0417MOD airfoil section was tested under two dimensional steady state conditions ate University 7 x 10 Subsonic Wind Tunnel. The objective was to document section lift and moment characteristics model and air flow conditions. Surface pressure data was acquired at -60° through + 230° geometric angles of attack, at a nominal 1 million Reynolds number. Cases with and without leading edge grit roughness were investigated. The leading edge mulated blade conditions in the field. Additionally, surface pressure data were acquired for Reynolds numbers of 1.5 and 2.0 million, with and without leading edge grit roughness; the angle of attack was limited to a -20° to 40° range. In general, results showed lift curve slope sensitivities to Reynolds number and roughness. The maximum lift coefficient was reduced as much as 29% by leading edge roughness. Moment coefficient showed little sensitivity to roughness beyond 50° angle of attack, but the expected decambering effect of a thicker boundary layer with roughness did show at lower angles. Tests were also conducted with vortex generators located at the 30% chord location on the upper surface only, at 1 and 1.5 million Reynolds numbers, with and without leading edge grit roughness. In general, with leading edge grit roughness applied, the vortex generators restored 85 percent of the baseline level of maximum lift coefficient but with a more sudden stall break and at a higher angle of attack than the baseline.

Download or read book Aerodynamics of Wind Turbines written by Sven Schmitz and published by John Wiley & Sons. This book was released on 2020-01-28 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: A review of the aerodynamics, design and analysis, and optimization of wind turbines, combined with the author’s unique software Aerodynamics of Wind Turbines is a comprehensive introduction to the aerodynamics, scaled design and analysis, and optimization of horizontal-axis wind turbines. The author –a noted expert on the topic – reviews the fundamentals and basic physics of wind turbines operating in the atmospheric boundary layer. He then explores more complex models that help in the aerodynamic analysis and design of turbine models. The text contains unique chapters on blade element momentum theory, airfoil aerodynamics, rotational augmentation, vortex-wake methods, actuator-line modeling, and designing aerodynamically scaled turbines for model-scale experiments. The author clearly demonstrates how effective analysis and design principles can be used in a wide variety of applications and operating conditions. The book integrates the easy-to-use, hands-on XTurb design and analysis software that is available on a companion website for facilitating individual analyses and future studies. This component enhances the learning experience and helps with a deeper and more complete understanding of the subject matter. This important book: Covers aerodynamics, design and analysis and optimization of wind turbines Offers the author’s XTurb design and analysis software that is available on a companion website for individual analyses and future studies Includes unique chapters on blade element momentum theory, airfoil aerodynamics, rotational augmentation, vortex-wake methods, actuator-line modeling, and designing aerodynamically scaled turbines for model-scale experiments Demonstrates how design principles can be applied to a variety of applications and operating conditions Written for senior undergraduate and graduate students in wind energy as well as practicing engineers and scientists, Aerodynamics of Wind Turbines is an authoritative text that offers a guide to the fundamental principles, design and analysis of wind turbines.

Download or read book Wind Turbine Airfoils and Blades written by Jin Chen and published by Walter de Gruyter GmbH & Co KG. This book was released on 2017-12-04 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind Turbine Airfoils and Blades introduces new ideas in the design of wind turbine airfoils and blades based on functional integral theory and the finite element method, accompanied by results from wind tunnel testing. The authors also discuss the optimization of wind turbine blades as well as results from aerodynamic analysis. This book is suitable for researchers and engineers in aeronautics and can be used as a textbook for graduate students.