Download or read book Rotor wing Aerodynamic Interactions in Hover written by and published by . This book was released on 1986 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rotor Wing Interactions in Hover written by and published by . This book was released on 2002 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rotor Wing Interactions in Hover 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 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hover predictions of tiltrotor aircraft are hampered by the lack of accurate and computationally efficient models for rotor/wing interactional aerodynamics. This paper summarizes the development of an approximate, potential flow solution for the rotor-on-rotor and wing-on-rotor interactions. This analysis is based on actuator disk and vortex theory and the method of images. The analysis is applicable for out-of-ground-effect predictions. The analysis is particularly suited for aircraft preliminary design studies. Flow field predictions from this simple analytical model are validated against experimental data from previous studies. The paper concludes with an analytical assessment of the influence of rotor-on-rotor and wing-on-rotor interactions. This assessment examines the effect of rotor-to-wing offset distance, wing sweep, wing span, and flaperon incidence angle on tiltrotor inflow and performance.Young, Larry A. and Derby, Michael R.Ames Research CenterFLOW DISTRIBUTION; MATHEMATICAL MODELS; ROTOR AERODYNAMICS; TILT ROTOR AIRCRAFT; INTERACTIONAL AERODYNAMICS; HOVERING; AIRCRAFT DESIGN; SWEPT WINGS; POTENTIAL FLOW; VORTICES; WING SPAN; FLAPERONS
Download or read book Rotor body Aerodynamic Interactions written by Mark D. Betzina and published by . This book was released on 1983 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wind-tunnel investigation was conducted in which independent, steady-state aerodynamic forces and moments were measured on a 2.24-m-diam, two- bladed helicopter rotor and on several different bodies. The objective was to determine the mutual interaction effects for variations in velocity, thrust, tip-path-plane angle of attack, body angle of attack, rotor/body position, and body geometry. the results of the investigation show that the body longitudinal aerodynamic characteristics are significantly affected by the presence of a rotor and hub, and that the hub interference may be a major part of such interaction. This report presents the effects of various parameters on the interactions and discusses the difficulties encountered in determining the effect of the body on the rotor performance.
Download or read book Rotary Wing Aerodynamics written by W. Z. Stepniewski and published by Courier Corporation. This book was released on 2013-04-22 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt: DIVClear, concise text covers aerodynamic phenomena of the rotor and offers guidelines for helicopter performance evaluation. Originally prepared for NASA. Prefaces. New Indexes. 10 black-and-white photos. 537 figures. /div
Download or read book Effects of Aerodynamic Interaction Between Main and Tail Rotors on Helicopter Hover Performance and Noise written by and published by . This book was released on 1983 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Aerodynamic Interaction Between Main and Tail Rotors on Helicopter Hover Performance and Noise written by Ross P. Menger and published by . This book was released on 1985 with total page 343 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Principles of Helicopter Aerodynamics with CD Extra written by Gordon J. Leishman and published by Cambridge University Press. This book was released on 2006-04-24 with total page 860 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Special Opportunities in Helicopter Aerodynamics written by W. J. McCroskey and published by . This book was released on 1983 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerodynamic research relating to modern helicopters includes the study of three-dimensional, unsteady, nonlinear flow fields. A selective review is made of some of the phenomenon that hamper the development of satisfactory engineering prediction techniques, but which provides a rich source of research opportunities: flow separations, compressibility effects, complex vortical wakes, and aerodynamic interference between components. Several examples of work in progress are given, including dynamic stall alleviation, the development of computational methods for transonic flow, rotor-wake predictions, and blade-vortex interactions. (Author).
Download or read book Aerodynamic Interactions Between a 1 6 Scale Helicopter Rotor and a Body of Revolution written by and published by . This book was released on 1982 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wind-tunnel investigation was conducted in which independent, steady-state aerodynamic forces and moments were measured on a 2.24-m-diam, two-bladed helicopter rotor and a body of revolution. The objective was to determine the interaction of the body on the rotor performance and the effect of the rotor on the body aerodynamics for variations in velocity, thrust, tip-path-plane angle of attack, body angle of attack, rotor/body position, and body nose geometry. Results show that a body of revolution near the rotor can produce significant favorable or unfavorable effects on rotor performance, depending on the operating condition. Body longitudinal aerodynamic characteristics are significantly modified by the presence of an operating rotor and hub. (Author).
Download or read book Simulation of Advanced Rotorcraft Concepts Using Free Wake Aerodynamic Models written by Andrew Jue and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation of the flight dynamics of two different electric vertical takeoff and landing aircraft was performed using the Distributed Electric Propulsion Simulation (DEPSim). DEPSim incorporates a free-wake model that allows for prediction of aerodynamic interactions, so the use of DEPSim allows for investigation of the effects that aerodynamic interactions can have on flight dynamics. One of the two aircraft studied was a generic lift+cruise multicopter proposed for urban air mobility (UAM) use. The aircraft has four lift rotors in a quad configuration along with a wing, tail, and pusher propeller. The other aircraft studied was the Dragonfly octocopter planned for exploration of Saturn's moon Titan. It is a multicopter with four coaxial rotor pairs arranged in a quad configuration. For both aircraft, a variety of dynamic maneuvers were investigated. Specifically, for the lift+cruise aircraft, departure maneuvers and approach maneuvers were investigated. For these maneuvers, the flight dynamics were analyzed in addition to the power and energy consumption. The departure simulations, which compared different ways to transition to wing-borne flight, showed that the departure maneuver that reached wing-borne flight the quickest used the least energy, 58% of the energy of the maneuver that reached wing-borne flight the slowest. Additionally, significant rotor-wing interference was observed for this aircraft in both departure and approach maneuvers. This interference arises from changes in the effective angle of attack on the wing due to the induced velocity from the rotor wake. These angle of attack changes are correlated with the thrust differential of the front rotors and result in the generation of a rolling moment by the wings due to lift asymmetry. It was found that thrust differentials between the front two rotors resulted in a significant rolling moment that was close to 4 times the pusher propeller torque. A change in control allocation alleviated the problem and reduced the rolling moment. For the approach maneuvers, it was found that the effect of both the rolling moment from interference and the change in control allocation depended on the aircraft pitch during the maneuver. For Dragonfly, the transition to powered flight maneuver was investigated. Additionally, the dynamics of the aircraft were studied through the calculation of stability derivatives and linear models at hover, 1 m/s, 5 m/s, and 10.5 m/s. The transition to powered flight, along with select stability and control derivatives, were compared to reference data for verification. For the transition to powered flight, two separate versions were performed: one had the rotors running throughout the entire simulation while another included the rotor start-up component of the maneuver. Both maneuvers were able to track the reference data fairly well with predicted rear rotor speed and rotor thrust slightly higher than the reference data. Two versions of the stability and control derivatives were also generated. One version included wing struts in the model while the other did not, and a small impact on the results generated was seen due to the aerodynamic interference with the wing struts. Overall, the stability and control derivatives matched well with the reference data even with the different aerodynamic interactions. This shows decent verification of the reference data with the DEPSim aerodynamic model and the interactions the model captures.
Download or read book An Unsteady Helicopter Rotor written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-17 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: A computational method was developed to treat unsteady aerodynamic interactions between a helicopter rotor, wake, and fuselage and between the main and tail rotors. An existing lifting line prescribed wake rotor analysis and a source panel fuselage analysis were coupled and modified to predict unsteady fuselage surface pressures and airloads. A prescribed displacement technique is used to position the rotor wake about the fuselage. Either a rigid blade or an aeroelastic blade analysis may be used to establish rotor operating conditions. Sensitivity studies were performed to determine the influence of the wake fuselage geometry on the computation. Results are presented that describe the induced velocities, pressures, and airloads on the fuselage and on the rotor. The ability to treat arbitrary geometries is demonstrated using a simulated helicopter fuselage. The computational results are compared with fuselage surface pressure measurements at several locations. No experimental data was available to validate the primary product of the analysis: the vibratory airloads on the entire fuselage. A main rotor-tail rotor interaction analysis is also described, along with some hover and forward flight. Lorber, Peter F. and Egolf, T. Alan Unspecified Center COMPUTATIONAL FLUID DYNAMICS; CONFIGURATION INTERACTION; INTERACTIONAL AERODYNAMICS; ROTARY WINGS; UNSTEADY AERODYNAMICS; UNSTEADY FLOW; AERODYNAMIC LOADS; FUSELAGES; HELICOPTER WAKES; HORIZONTAL FLIGHT; HOVERING; PRESSURE EFFECTS...
Download or read book Fundamentals of fixed and rotary wing aerodynamics written by and published by . This book was released on 1984 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Performance Computing in Science and Engineering 18 written by Wolfgang E. Nagel and published by Springer. This book was released on 2019-06-07 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the state-of-the-art in supercomputer simulation. It includes the latest findings from leading researchers using systems from the High Performance Computing Center Stuttgart (HLRS) in 2018. The reports cover all fields of computational science and engineering ranging from CFD to computational physics and from chemistry to computer science with a special emphasis on industrially relevant applications. Presenting findings of one of Europe’s leading systems, this volume covers a wide variety of applications that deliver a high level of sustained performance. The book covers the main methods in high-performance computing. Its outstanding results in achieving the best performance for production codes are of particular interest for both scientists and engineers. The book comes with a wealth of color illustrations and tables of results.
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on with total page 1200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
