Database of Inlet and Exhaust Noise Shielding for Wedge-shaped Airframe

Database of Inlet and Exhaust Noise Shielding for Wedge-shaped Airframe PDF Author: Carl H. Gerhold
Publisher:
ISBN:
Category : Aerodynamic noise
Languages : en
Pages : 22

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Book Description
An experiment to measure the noise shielding of the blended wing body design concept was developed using a simplified wedge-shaped airframe. The experimental study was conducted in the Langley Anechoic Noise Research facility. A wideband, omnidirective sound source in a simulated engine nacelle was held at locations representative of a range of engine locations above the wing. The sound field around the model was measured, with the airframe and source in place and with source alone, using an array of microphones on a rotating hoop that is also translated along an axis parallel to the airframe axis. The insertion loss was determined from the difference between the two resulting contours. Although no attempt was made to simulate the noise characteristics of a particular engine, the broadband noise source radiated sound over a range of scaled frequencies encompassing 1 and 2 times the blade passage frequency representative of a large, high-bypass-ratio turbofan engine.

Database of Inlet and Exhaust Noise Shielding for Wedge-shaped Airframe

Database of Inlet and Exhaust Noise Shielding for Wedge-shaped Airframe PDF Author: Carl H. Gerhold
Publisher:
ISBN:
Category : Aerodynamic noise
Languages : en
Pages : 22

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Book Description
An experiment to measure the noise shielding of the blended wing body design concept was developed using a simplified wedge-shaped airframe. The experimental study was conducted in the Langley Anechoic Noise Research facility. A wideband, omnidirective sound source in a simulated engine nacelle was held at locations representative of a range of engine locations above the wing. The sound field around the model was measured, with the airframe and source in place and with source alone, using an array of microphones on a rotating hoop that is also translated along an axis parallel to the airframe axis. The insertion loss was determined from the difference between the two resulting contours. Although no attempt was made to simulate the noise characteristics of a particular engine, the broadband noise source radiated sound over a range of scaled frequencies encompassing 1 and 2 times the blade passage frequency representative of a large, high-bypass-ratio turbofan engine.

Database of Inlet and Exhaust Noise Shielding for Wedge-Shaped Airframe

Database of Inlet and Exhaust Noise Shielding for Wedge-Shaped Airframe PDF Author: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
ISBN: 9781724112699
Category : Science
Languages : en
Pages : 36

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Book Description
An experiment to measure the noise shielding of the blended wing body design concept was developed using a simplified wedge-shaped airframe. The experimental study was conducted in the Langley Anechoic Noise Research Facility. A wideband, omnidirective sound source in a simulated engine nacelle was held at locations representative of a range of engine locations above the wing. The sound field around the model was measured with the airframe and source in place and with source alone, using an-array of microphones on a rotating hoop that is also translated along an axis parallel to the airframe axis. The insertion loss was determined from the difference between the two resulting contours. Although no attempt was made to simulate the noise characteristics of a particular engine, the broadband noise source radiated sound over a range of scaled frequencies encompassing 1 and 2 times the blade passage frequency representative of a large, high-bypass-ratio turbofan engine. The measured data show that significant shielding of the inlet-radiated noise is obtained in the area beneath and upstream of the model. The data show the sensitivity of insertion loss to engine location. Gerhold, Carl H. and Clark, Lorenzo R. Langley Research Center NASA/TM-2001-210840, L-18053, NAS 1.15:210840

NASA Langley Scientific and Technical Information Output-2001

NASA Langley Scientific and Technical Information Output-2001 PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 166

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AIAA Journal

AIAA Journal PDF Author: American Institute of Aeronautics and Astronautics
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 990

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NASA Tech Briefs

NASA Tech Briefs PDF Author:
Publisher:
ISBN:
Category : Technology
Languages : en
Pages : 526

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Active Radar Cross Section Reduction

Active Radar Cross Section Reduction PDF Author: Hema Singh
Publisher: Cambridge University Press
ISBN: 1107092612
Category : History
Languages : en
Pages : 354

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Book Description
This book discusses the active and passive radar cross section (RCS) estimation and techniques to examine the low observable aerospace platforms. It begins with the fundamentals of RCS, followed by the dielectric, magnetic and metamaterials parameters of the constituent materials and then explains various methods and the emerging trends followed in this area of study. The RCS estimation of phased array including the mutual coupling effect is also presented in detail in the book. The active RCS reduction is carefully touched upon through the performance of phased arrays, sidelobe cancellers and mitigation of multipath effect. Providing information on various adaptive algorithms like least mean square (LMS), recursive least square (RLS) and weighted least square algorithms, the authors also mention the recent developments in the area of embedded antennas, conformal load bearing antenna, metamaterials and frequency selective surface (FSS) based RCS reduction.

Environmental Quality Research and Development: a Review and Analysis of Federal Programs

Environmental Quality Research and Development: a Review and Analysis of Federal Programs PDF Author: Federal Council for Science and Technology (U.S.). Ad Hoc Committee on Environmental Quality Research and Development
Publisher:
ISBN:
Category : Environmental engineering
Languages : en
Pages : 152

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Airport & Airline Management

Airport & Airline Management PDF Author:
Publisher:
ISBN:
Category : Airlines
Languages : en
Pages : 410

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Airports and Airport Engineering

Airports and Airport Engineering PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 498

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Evaluation of a Hydrogen Fuel Cell Powered Blended-Wing-Body Aircraft Concept for Reduced Noise and Emissions

Evaluation of a Hydrogen Fuel Cell Powered Blended-Wing-Body Aircraft Concept for Reduced Noise and Emissions PDF Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781720511922
Category :
Languages : en
Pages : 46

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Book Description
This report describes the analytical modeling and evaluation of an unconventional commercial transport aircraft concept designed to address aircraft noise and emission issues. A blended-wing-body configuration with advanced technology hydrogen fuel cell electric propulsion is considered. Predicted noise and emission characteristics are compared to a current technology conventional configuration designed for the same mission. The significant technology issues which have to be addressed to make this concept a viable alternative to current aircraft designs are discussed. This concept is one of the "Quiet Green Transport" aircraft concepts studied as part of NASA's Revolutionary Aerospace Systems Concepts (RASC) Program. The RASC Program was initiated to develop revolutionary concepts that address strategic objectives of the NASA Enterprises, such as reducing aircraft noise and emissions, and to identify advanced technology requirements for the concepts.Guynn, Mark D. and Freh, Joshua E. and Olson, Erik D.Glenn Research Center; Langley Research CenterMATHEMATICAL MODELS; EVALUATION; AIRCRAFT DESIGN; AIRCRAFT NOISE; NOISE REDUCTION; AEROSPACE SYSTEMS; BLENDED-WING-BODY CONFIGURATIONS; COMMERCIAL AIRCRAFT; ELECTRIC PROPULSION; FUEL CELLS; NOISE MEASUREMENT