Large Civil Tiltrotor (Lctr2) Interior Noise Predictions Due to Turbulent Boundary Layer Excitation
Large Civil Tiltrotor (Lctr2) Interior Noise Predictions Due to Turbulent Boundary Layer Excitation

Author: National Aeronautics and Space Adm Nasa

Publisher: Independently Published

Published: 2019-01-14

Total Pages: 44

ISBN-13: 9781794075979

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The Large Civil Tiltrotor (LCTR2) is a conceptual vehicle that has a design goal to transport 90 passengers over a distance of 1800 km at a speed of 556 km/hr. In this study noise predictions were made in the notional LCTR2 cabin due to Cockburn/Robertson and Efimtsov turbulent boundary layer (TBL) excitation models. A narrowband hybrid Finite Element (FE) analysis was performed for the low frequencies (6-141 Hz) and a Statistical Energy Analysis (SEA) was conducted for the high frequency one-third octave bands (125- 8000 Hz). It is shown that the interior sound pressure level distribution in the low frequencies is governed by interactions between individual structural and acoustic modes. The spatially averaged predicted interior sound pressure levels for the low frequency hybrid FE and the high frequency SEA analyses, due to the Efimtsov turbulent boundary layer excitation, were within 1 dB in the common 125 Hz one-third octave band. The averaged interior noise levels for the LCTR2 cabin were predicted lower than the levels in a comparable Bombardier Q400 aircraft cabin during cruise flight due to the higher cruise altitude and lower Mach number of the LCTR2. LCTR2 cabin noise due to TBL excitation during cruise flight was found not unacceptable for crew or passengers when predictions were compared to an acoustic survey on a Q400 aircraft. NASA/CR-2013-218005, NF1676L-16365 Grosveld, Ferdinand W. Langley Research Center

Rotorcraft Aeromechanics
Rotorcraft Aeromechanics

Author: Wayne Johnson

Publisher: Cambridge University Press

Published: 2013-04-29

Total Pages: 949

ISBN-13: 1107355281

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A rotorcraft is a class of aircraft that uses large-diameter rotating wings to accomplish efficient vertical take-off and landing. The class encompasses helicopters of numerous configurations (single main rotor and tail rotor, tandem rotors, coaxial rotors), tilting proprotor aircraft, compound helicopters, and many other innovative configuration concepts. Aeromechanics covers much of what the rotorcraft engineer needs: performance, loads, vibration, stability, flight dynamics, and noise. These topics include many of the key performance attributes and the often-encountered problems in rotorcraft designs. This comprehensive book presents, in depth, what engineers need to know about modelling rotorcraft aeromechanics. The focus is on analysis, and calculated results are presented to illustrate analysis characteristics and rotor behaviour. The first third of the book is an introduction to rotorcraft aerodynamics, blade motion, and performance. The remainder of the book covers advanced topics in rotary wing aerodynamics and dynamics.

Decadal Survey of Civil Aeronautics
Decadal Survey of Civil Aeronautics

Author: National Research Council

Publisher: National Academies Press

Published: 2006-10-27

Total Pages: 212

ISBN-13: 0309101581

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The U.S. air transportation system is very important for our economic well-being and national security. The nation is also the global leader in civil and military aeronautics, a position that needs to be maintained to help assure a strong future for the domestic and international air transportation system. Strong action is needed, however, to ensure that leadership role continues. To that end, the Congress and NASA requested the NRC to undertake a decadal survey of civil aeronautics research and technology (R&T) priorities that would help NASA fulfill its responsibility to preserve U.S. leadership in aeronautics technology. This report presents a set of strategic objectives for the next decade of R&T. It provides a set of high-priority R&T challengesâ€"-characterized by five common themesâ€"-for both NASA and non-NASA researchers, and an analysis of key barriers that must be overcome to reach the strategic objectives. The report also notes the importance of synergies between civil aeronautics R&T objectives and those of national security.

The DelFly
The DelFly

Author: G.C.H.E. de Croon

Publisher: Springer

Published: 2015-11-26

Total Pages: 221

ISBN-13: 9401792089

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This book introduces the topics most relevant to autonomously flying flapping wing robots: flapping-wing design, aerodynamics, and artificial intelligence. Readers can explore these topics in the context of the "Delfly", a flapping wing robot designed at Delft University in The Netherlands. How are tiny fruit flies able to lift their weight, avoid obstacles and predators, and find food or shelter? The first step in emulating this is the creation of a micro flapping wing robot that flies by itself. The challenges are considerable: the design and aerodynamics of flapping wings are still active areas of scientific research, whilst artificial intelligence is subject to extreme limitations deriving from the few sensors and minimal processing onboard. This book conveys the essential insights that lie behind success such as the DelFly Micro and the DelFly Explorer. The DelFly Micro, with its 3.07 grams and 10 cm wing span, is still the smallest flapping wing MAV in the world carrying a camera, whilst the DelFly Explorer is the world's first flapping wing MAV that is able to fly completely autonomously in unknown environments. The DelFly project started in 2005 and ever since has served as inspiration, not only to many scientific flapping wing studies, but also the design of flapping wing toys. The combination of introductions to relevant fields, practical insights and scientific experiments from the DelFly project make this book a must-read for all flapping wing enthusiasts, be they students, researchers, or engineers.

The Aerodynamics of Heavy Vehicles III
The Aerodynamics of Heavy Vehicles III

Author: Andreas Dillmann

Publisher: Springer

Published: 2015-08-19

Total Pages: 416

ISBN-13: 3319201220

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This volume contains papers presented at the International conference “The Aerodynamics of Heavy Vehicles III: Trucks, Buses and Trains” held in Potsdam, Germany, September 12-17, 2010 by Engineering Conferences International (ECI). Leading scientists and engineers from industry, universities and research laboratories, including truck and high-speed train manufacturers and operators were brought together to discuss computer simulation and experimental techniques to be applied for the design of more efficient trucks, buses and high-speed trains in the future. This conference was the third in the series after Monterey-Pacific Groove in 2002 and Lake Tahoe in 2007.The presentations address different aspects of train aerodynamics (cross wind effects, underbody flow, tunnel aerodynamics and aeroacoustics, experimental techniques), truck aerodynamics (drag reduction, flow control, experimental and computational techniques) as well as computational fluid dynamics and bluff body, wake and jet flows.

V-22 Osprey Tilt-Rotor Aircraft
V-22 Osprey Tilt-Rotor Aircraft

Author: Ronald O'Rourke

Publisher: DIANE Publishing

Published: 2009-11

Total Pages: 27

ISBN-13: 1437918778

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The V-22 Osprey is a tilt-rotor aircraft that takes off and lands vertically like a helicopter and flies forward like an airplane. DoD plans call for procuring a total of 458 V-22s. Contents of this report: (1) Intro.; (2) The V-22 In Brief; Intended Missions; Key Contractors; Total and Annual Procurement Quantities; Multiyear Procurement for FY2008-FY2012; Est. Total Program Cost; Prior-Year Funding; FY2010 Funding Request; Request for MV-22s; Request for CV-22s; Program History in Brief; Deployment to Iraq; Anticipated 2009 Deployment to Afghanistan; Foreign Military Sales; (3) Aircraft Reliability and Maintainability; Other Potential Issues; (4) Legislative Activity in 2009; May 21, 2009, Hearing on V-22 Program. Illustrations.

Flight Vehicle Aerodynamics
Flight Vehicle Aerodynamics

Author: Mark Drela

Publisher: MIT Press

Published: 2014-02-07

Total Pages: 304

ISBN-13: 0262526441

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An overview of the physics, concepts, theories, and models underlying the discipline of aerodynamics. This book offers a general overview of the physics, concepts, theories, and models underlying the discipline of aerodynamics. A particular focus is the technique of velocity field representation and modeling via source and vorticity fields and via their sheet, filament, or point-singularity idealizations. These models provide an intuitive feel for aerodynamic flow-field behavior and are the basis of aerodynamic force analysis, drag decomposition, flow interference estimation, and other important applications. The models are applied to both low speed and high speed flows. Viscous flows are also covered, with a focus on understanding boundary layer behavior and its influence on aerodynamic flows. The book covers some topics in depth while offering introductions and summaries of others. Computational methods are indispensable for the practicing aerodynamicist, and the book covers several computational methods in detail, with a focus on vortex lattice and panel methods. The goal is to improve understanding of the physical models that underlie such methods. The book also covers the aerodynamic models that describe the forces and moments on maneuvering aircraft, and provides a good introduction to the concepts and methods used in flight dynamics. It also offers an introduction to unsteady flows and to the subject of wind tunnel measurements. The book is based on the MIT graduate-level course “Flight Vehicle Aerodynamics” and has been developed for use not only in conventional classrooms but also in a massive open online course (or MOOC) offered on the pioneering MOOC platform edX. It will also serve as a valuable reference for professionals in the field. The text assumes that the reader is well versed in basic physics and vector calculus, has had some exposure to basic fluid dynamics and aerodynamics, and is somewhat familiar with aerodynamics and aeronautics terminology.