The Influence of Sweep on the Aerodynamic Loading of an Oscillating NACA 0012 Airfoil
Author :
Publisher :
Page : 148 pages
File Size : 50,63 MB
Release : 1979
Category : Aerodynamics
ISBN :
Author :
Publisher :
Page : 148 pages
File Size : 50,63 MB
Release : 1979
Category : Aerodynamics
ISBN :
Author : Gordon J. Leishman
Publisher : Cambridge University Press
Page : 860 pages
File Size : 33,4 MB
Release : 2006-04-24
Category : Science
ISBN : 9780521858601
Written by an internationally recognized teacher and researcher, this book provides a thorough, modern treatment of the aerodynamic principles of helicopters and other rotating-wing vertical lift aircraft such as tilt rotors and autogiros. The text begins with a unique technical history of helicopter flight, and then covers basic methods of rotor aerodynamic analysis, and related issues associated with the performance of the helicopter and its aerodynamic design. It goes on to cover more advanced topics in helicopter aerodynamics, including airfoil flows, unsteady aerodynamics, dynamic stall, and rotor wakes, and rotor-airframe aerodynamic interactions, with final chapters on autogiros and advanced methods of helicopter aerodynamic analysis. Extensively illustrated throughout, each chapter includes a set of homework problems. Advanced undergraduate and graduate students, practising engineers, and researchers will welcome this thoroughly revised and updated text on rotating-wing aerodynamics.
Author :
Publisher :
Page : 702 pages
File Size : 46,43 MB
Release : 1995
Category : Aeronautics
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Author : A. O. St. Hilaire
Publisher :
Page : 110 pages
File Size : 26,53 MB
Release : 1983
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ISBN :
The objective of the present investigation was to study the unsteady chordwise force response on the airfoil surface and to examine its sensitivity to the various system parameters. A further examination of previously reported unsteady aerodynamic data on a tunnel spanning with (both swept and unswept), obtained in the United Technologies Research (UTRC) Main Wind Tunnel, was performed. The main body of this data analysis was carried out by analyzing the propagation speed of pressure disturbances along the chord and by studying the behavior of the unsteady part of the chordwise pressure distribution at various points of the airfoil pitching cycle. It was found that Mach number effects dominate the approach to and the inception of both static and dynamic stall. The stall angle decreases as the Mach number increases. However, sweep dominates the load behavior within the stall regime. Large phase differences between unswept and swept responses, that do not exist at low lift coefficient, appear once the stall boundary has been penetrated. It was also found that reduced frequency is not a reliable indicator of the unsteady aerodynamic response in the high angle of attack regime. (Author).
Author : A. O. St. Hilaire
Publisher :
Page : 106 pages
File Size : 15,71 MB
Release : 1983
Category : Aerofoils
ISBN :
Author : J. Gordon Leishman
Publisher : Cambridge University Press
Page : 544 pages
File Size : 40,57 MB
Release : 2002-12-23
Category : Medical
ISBN : 9780521523967
Helicopters are highly capable and useful rotating-wing aircraft with roles that encompass a variety of civilian and military applications. Their usefulness lies in their unique ability to take off and land vertically, to hover stationary relative to the ground, and to fly forward, backward, or sideways. These unique flying qualities, however, come at a high cost including complex aerodynamic problems, significant vibrations, high levels of noise, and relatively large power requirements compared to fixed-wing aircraft. This book, written by an internationally recognized expert, provides a thorough, modern treatment of the aerodynamic principles of helicopters and other rotating-wing vertical lift aircraft. Every chapter is extensively illustrated and concludes with a bibliography and homework problems. Advanced undergraduate and graduate students, practising engineers, and researchers will welcome this thorough and up-to-date text on rotating-wing aerodynamics.
Author :
Publisher :
Page : 62 pages
File Size : 33,90 MB
Release : 2000
Category :
ISBN :
The loading of an airfoil during dynamic stall is examined in terms of the augmented lift and the associated penalties in pitching moment and drag. It is shown that once stall occurs and a leading-edge vortex is shed from the airfoil there is a unique relationship between the augmented lift, the negative pitching moment, and the increase in drag. This relationship, referred to here as the dynamic stall function, shows limited sensitivity to effects such as the airfoil section profile and Mach number, and appears to be independent of such parameters as Reynolds number, reduced frequency, and blade sweep. For single-element airfoils there is little that can be done to improve rotorcraft maneuverability except to provide good static clmax characteristics and the chord or blade number that is required to provide the necessary rotor thrust. However, multi-element airfoils or airfoils with variable geometry features can provide augmented lift in some cases that exceeds that available from a single-element airfoil. The dynamic stall function is shown to be a useful tool for the evaluation of both measured and calculated dynamic stall characteristics of singleelement, multi-element, and variable geometry airfoils.
Author : Anjaneyulu Krothapalli
Publisher : Springer Science & Business Media
Page : 752 pages
File Size : 21,32 MB
Release : 2012-12-06
Category : Science
ISBN : 1461249724
The Joint Institute for Aeronautics and Acoustics at Stanford University was established in October 1973 to provide an academic environment for long-term cooperative research between Stanford and NASA Ames Research Center. Since its establishment, the In stitute has wnducted theoretical and experimental work in the areas of aerodynamics, acoustics, fluid mechanics, flight dynamics, guid ance and control, and human factors. This research has involved Stanford faculty, research associates, graduate students, and many distinguished visitors in collaborative efforts with the research staff of NASA Ames Research Center. The occasion of the Institute's tenth anniversary was used to reflect back on where that research has brought us, and to consider where our endeavors should be directed next. Thus, an International Symposium was held to review recent advances in the fields relevant to the activities of the Institute and to discuss the areas of research to be undertaken in the future. This anniversary was also chosen a.."1 an opportunity to honor one of the Institute's founders and its di rector, Professor Krishnamurty Karamcheti. It has been his creative inspiration that has provided the ideal research environment at the Joint Institute. The International Symposium on Recent Advances in Aero dynamics and Aconstics was held at Stanford University, Stanford, California, U.S.A., August 22-26, 198:~. Thirty-five distinguished scientists were invited to present a comprehensive review on the fol lowing subject areas: unsteady aerodynamics, jets and shear layers, V /STOL aircraft aerodynamics, rotor dynamics and aerodynamics,.
Author : Franklin O. Carta
Publisher :
Page : 164 pages
File Size : 44,30 MB
Release : 1979
Category : Aerodynamics
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Author : S. J. Shamroth
Publisher :
Page : 116 pages
File Size : 21,1 MB
Release : 1985
Category : Aerodynamics
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