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Rotor Wake Vortex Definition
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Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781720712114 Total Pages :30 pages Book Rating :4.7/5 (121 download)
Book Synopsis Rotor Wake Vortex Definition by : National Aeronautics and Space Administration (NASA)
Download or read book Rotor Wake Vortex Definition written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-04 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: An initial evaluation is made of extensive three-component (3C) particle image velocimetry (PIV) measurements within the wake across a rotor disk plane. The model is a 40 percent scale BO-105 helicopter main rotor in forward flight simulation. This study is part of the HART II test program conducted in the German-Dutch Wind Tunnel (DNW). Included are wake vortex field measurements over the advancing and retreating sides of the rotor operating at a typical descent landing condition important for impulsive blade-vortex interaction (BVI) noise. Also included are advancing side results for rotor angle variations from climb to steep descent. Using detailed PIV vector maps of the vortex fields, methods of extracting key vortex parameters are examined and a new method was developed and evaluated. An objective processing method, involving a center-of-vorticity criterion and a vorticity 'disk' integration, was used to determine vortex core size, strength, core velocity distribution characteristics, and unsteadiness. These parameters are mapped over the rotor disk and offer unique physical insight for these parameters of importance for rotor noise and vibration prediction.Burley, Casey L. and Brooks, Thomas F. and vanderWall, Berend and Richard, Hughes and Raffel, Markus and Beaumier, Philippe and Delrieux, Yves and Lim, Joon W. and Yu, Yung H. and Tung, CheeAmes Research Center; Langley Research CenterROTOR AERODYNAMICS; VORTICES; WAKES; BO-105 HELICOPTER; ROTARY WINGS; WIND TUNNEL TESTS; PARTICLE IMAGE VELOCIMETRY; WIND TUNNELS; BLADE-VORTEX INTERACTION; BLADE SLAP NOISE
Download or read book Vortex Dominated Flows written by Lu Ting and published by World Scientific. This book was released on 2005 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: Honoring the contributions of one of the field''s leading experts, Lu Ting, this indispensable volume contains important new results at the cutting edge of research. A wide variety of significant new analytical and numerical results in critical areas are presented, including point vortex dynamics, superconductor vortices, cavity flows, vortex breakdown, shock/vortex interaction, wake flows, magneto-hydrodynamics, rotary wake flows, and hypersonic vortex phenomena. The book will be invaluable for those interested in the state of the art of vortex dominated flows, both from a theoretical and applied perspective. Professor Lu Ting and Joe Keller have worked together for over 40 years. In their first joint work entitled OC Periodic vibrations of systems governed by nonlinear partial differential equationsOCO, perturbation analysis and bifurcation theory were used to determine the frequencies and modes of vibration of various physical systems. The novelty was the application to partial differential equations of methods which, previously, had been used almost exclusively on ordinary differential equations. Professsor Lu Ting is an expert in both fluid dynamics and the use of matched asymptotic expansions. His physical insight into fluid flows has led the way to finding the appropriate mathematical simplications used in the solutions to many difficult flow problems."
Book Synopsis Free Wake Techniques for Rotor Aerodynamic Analylis. Volume 2: Vortex Sheet Models by :
Download or read book Free Wake Techniques for Rotor Aerodynamic Analylis. Volume 2: Vortex Sheet Models written by and published by . This book was released on 1982 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Analytical Model of Rotor Wake Aerodynamics in Ground Effect by :
Download or read book Analytical Model of Rotor Wake Aerodynamics in Ground Effect written by and published by . This book was released on 1983 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Experimental Investigation of the Far-field Rotorcraft Wake Structure by : James Harold Stephenson
Download or read book Experimental Investigation of the Far-field Rotorcraft Wake Structure written by James Harold Stephenson and published by . This book was released on 2012 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: The tumbling tip vortex effect of a reduced-scale, 1 m diameter, four-bladed rotor during hover is studied using vortex methods, combined with a center of mass analysis approach. Measurements of all three components of the velocity field are acquired using a stereo PIV system synchronized to capture up to 500 degrees of vortex age, with 10 degree wake age offsets, during hover conditions. The nominal operating condition of the rotor is at a rotational rate of 1520RPM, corresponding to ReC = 248,000 with a chord length of 58.5mm. The rotor is operated with a pitch of 7.2± 0.5 degrees and a CT/sigma of 0.045. The far wake vortex tumbling phenomenon is captured and described. It is shown that tip vortices from two blades tumble through approximately 90 degrees of rotation before they coalesce. It is also seen that the constituent parent vortices do not combine to create a stronger daughter vortex as was previously thought to happen. Instead, the merged vortex has a lower large-radius circulation than either of its parent vortices. An accurate characterization and prediction of the trajectory of the far wake vortex tumbling can enhance the ability to predict and alleviate the resuspension of particles during brownout as well as provide a database for far wake validation of CFD codes.
Book Synopsis An Experimental Investigation of the Vortex Wakes of Hovering and Descending Rotors by : James Anthony Stack
Download or read book An Experimental Investigation of the Vortex Wakes of Hovering and Descending Rotors written by James Anthony Stack and published by . This book was released on 2006 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Roll Up Model for Rotor Wake Vortices by : Mårten T. Landahl
Download or read book Roll Up Model for Rotor Wake Vortices written by Mårten T. Landahl and published by . This book was released on 1981 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Analysis of Rotor Wake Aerodynamics During Maneuvering Flight Using a Free-vortex Wake Methodology by :
Download or read book Analysis of Rotor Wake Aerodynamics During Maneuvering Flight Using a Free-vortex Wake Methodology written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Helicopter Rotor Wake Geometry and Its Influence in Forward Flight. Volume 2: Wake Geometry Charts by : T. Alan Egolf
Download or read book Helicopter Rotor Wake Geometry and Its Influence in Forward Flight. Volume 2: Wake Geometry Charts written by T. Alan Egolf and published by . This book was released on 1983 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Evaluation of Linearized Vortex Theory as Applied to Single and Multiple Rotors Hovering in and Out of Ground Effect by : Harry H. Heyson
Download or read book An Evaluation of Linearized Vortex Theory as Applied to Single and Multiple Rotors Hovering in and Out of Ground Effect written by Harry H. Heyson and published by . This book was released on 1959 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Analytical and Experimental Study of Farfield Rotor Wake Geometry and Velocity by : Thomas Alan Egolf
Download or read book An Analytical and Experimental Study of Farfield Rotor Wake Geometry and Velocity written by Thomas Alan Egolf and published by . This book was released on 1973 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: All fixed wing aircraft generate trailing vortex wakes whose circulatory strength is dependent on flight conditions and aircraft geometry. A rotor also generates a vortex wake. A vortex sheet is shed from each blade. Each sheet rolls up rapidly outboard to form a tip vortex. The purpose of the study reported here is to estimate the rotor wake geometry and velocity field downstream of the rotor for the particular case where the rotor wake exhibits strong similarities to the fixed wing wake. A method is developed by which the helicopter far field wake can be readily compared to the far field wake generated by an equivalent wing. (Author).
Book Synopsis Free Wake Techniques for Rotor Aerodynamic Analysis. Volume 1: Summary of Results and Background Theory by :
Download or read book Free Wake Techniques for Rotor Aerodynamic Analysis. Volume 1: Summary of Results and Background Theory written by and published by . This book was released on 1982 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Method for Assessing the Impact of Wake Vortices of USAF Operations by : George Kurylowich
Download or read book A Method for Assessing the Impact of Wake Vortices of USAF Operations written by George Kurylowich and published by . This book was released on 1979 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experience as a consultant to the Safety Office at Norton AFB led to compiling the engineering tools presented so that this report can be used by engineering personnel to investigate future incidents/accidents and existing USAF operations that are impacted by the vortical wake hazard. The approach presented is amenable to easy hand computations. Mixed airplane/helicopter operations can be assessed, since the engineering tools to determine the location and strength of the rotor downwash field behind a helicopter are presented. Finally, a simplified mathematical model is given to represent this hazard for use in USAF simulators, to make pilots aware of the problems associated with operating in wake-contaminated airspace.
Book Synopsis The Origin and Structure of Trailing Vortices in Aerodynamics by :
Download or read book The Origin and Structure of Trailing Vortices in Aerodynamics written by and published by . This book was released on 2001 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: The helicopter rotor wake is among the most complex flow-fields in aerodynamics. Despite the fact that a large amount of computational and experimental work on the rotor wake has been published, little of a quantitative nature is known about the origin of the main component of the rotor wake, the tip-vortex, as a function of the rotor speed, rotor blade geometry, and angle of attack. The primary objective of this work is to predict the formation of the rotor tip vortex as a function of physical parameters such as angle of attack, rotor speed, and blade aspect ratio. While the rotor-blade tip-vortex is of primary interest, the techniques developed are applicable to fixed wings as well.
Book Synopsis Vortex Core Size in the Rotor Near-Wake by :
Download or read book Vortex Core Size in the Rotor Near-Wake written by and published by . This book was released on 2003 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Principles of Helicopter Aerodynamics by : J. Gordon Leishman
Download or read book Principles of Helicopter Aerodynamics written by J. Gordon Leishman and published by Cambridge University Press. This book was released on 2002-12-23 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Fundamentals of Helicopter Dynamics by : C. Venkatesan
Download or read book Fundamentals of Helicopter Dynamics written by C. Venkatesan and published by CRC Press. This book was released on 2014-08-19 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: Helicopter Dynamics Introduced in an Organized and Systematic Manner A result of lecture notes for a graduate-level introductory course as well as the culmination of a series of lectures given to designers, engineers, operators, users, and researchers, Fundamentals of Helicopter Dynamics provides a fundamental understanding and a thorough overview of helicopter dynamics and aerodynamics. Written at a basic level, this text starts from first principles and moves fluidly onward from simple to more complex systems. Gain Valuable Insight on Helicopter Theory Divided into 11 chapters, this text covers historical development, hovering and vertical flight, simplified rotor blade model in flap mode, and forward flight. It devotes two chapters to the aeroelastic response and stability analysis of isolated rotor blade in uncoupled and coupled modes. Three chapters address the modeling of coupled rotor–fuselage dynamics and the associated flight dynamic stability, and provide a simplified analysis of the ground resonance aeromechanical stability of a helicopter. Explains equations derived from first principles and approximations Contains a complete set of equations which can be used for preliminary studies Requires a basic first–level course in dynamics, as well as a basic first–level course in aerodynamics Useful for any student who wants to learn the complexities of dynamics in a flying vehicle, Fundamentals of Helicopter Dynamics is an ideal resource for aerospace/aeronautical, helicopter, and mechanical/control engineers, as well as air force schools and helicopter/rotorcraft manufacturers.
