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Tuesday, May 19, 2020 | History

3 edition of Database of inlet and exhaust noise shielding for wedge-shaped airframe found in the catalog.

Database of inlet and exhaust noise shielding for wedge-shaped airframe

Carl H. Gerhold

Database of inlet and exhaust noise shielding for wedge-shaped airframe

by Carl H. Gerhold

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Published by National Aeronautics and Space Administration, Langley Research Center, Available from NASA Center for AeroSpace Information (CASI) in Hampton, Va, Hanover, MD .
Written in English


Edition Notes

StatementCarl H. Gerhold and Lorenzo R.Clark.
Series[NASA technical memorandum] -- NASA/TM-2001-210840., NASA technical memorandum -- 210840.
ContributionsClark, Lorenzo R., Langley Research Center.
The Physical Object
Pagination1 v.
ID Numbers
Open LibraryOL17607368M
OCLC/WorldCa50743536

Another major component of exhaust noise, particularly when an airplane engine is bugling through tubular headers rather than an ordinary cast-iron automotive exhaust manifold, is the impact of the shock wave of every single exhaust pulse upon the thin stainless-steel pipe wall nearest the exhaust valve. The noise suppressors in current use are either of the corrugated-perimeter type, or the multi-tube type. [Figure 2] Both types of suppressors break up the single, main jet exhaust stream into a number of smaller jet streams.

Heating, Air Conditioning, Ventilation and Air Distribution Products Web Line Direct Help Line • Noise from AHU A and B was audible in the center of the fourth floor. • Noise level on the fourth floor with units running averaged 46 dBA in the middle of the floor. • Noise from air-handling units on the south and north end of the building was audible with vibration that could be felt on the Size: KB.

II. Jet Noise Suppression Jet exhaust is one of the dominant noise sources that dramatically increases with throttle push from modern turbofan engines.3 Jet noise can be attributed to the turbulent mixing of the hot jet exhaust (core), bypass stream (fan), and ambient air; therefore,File Size: KB. inlet to the outlet of a system component. Acoustics The science that is related to the production, control, transmission, reception, and effects of sound. Acoustic Media The sound-absorbing material used inside absorptive type silencers and plenum walls. Ambient Noise An all-encompassing noise that is present in a given environment and is.


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Database of inlet and exhaust noise shielding for wedge-shaped airframe by Carl H. Gerhold Download PDF EPUB FB2

Significant inlet noise shielding, but the model could not be altered; therefore the effects of the variation of design parameters could not be assessed.

A follow-on experiment was developed by using a simplified wedge-shaped airframe, for which the engine nacelle placement is varied. The noise shielding database.

Inlet-radiated noise is shielded in the area below the aircraft by the wing upper surface. A recently completed study on an early model of the BWB concept airframe verified significant shield-ing of the inlet-radiated noise by the fuselage (ref. In addition to verifying inlet noise shielding, the dataCited by: 8.

Database of Inlet and Exhaust Noise Shielding for Wedge-Shaped Airframe. Calculated insertion loss of wedge-shaped airframe, source at inlet of duct, and 20 kHz frequency.

Database of. Database of inlet and exhaust noise shielding for wedge-shaped airframe. [Carl H Gerhold; Lorenzo R Clark; Langley Research Center,] -- An experiment to measure the noise shielding of the blended wing body design concept was developed using a simplified wedge-shaped airframe.

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.

BibTeX @MISC{And01databaseof, author = {Carl Gerhold And and Carl H. Gerhold and Lorenzo R. Clark}, title = {Database of Inlet and Exhaust Noise Shielding for Wedge-Shaped Airframe.

Database of Inlet and Exhaust Noise Shielding for Wedge-Shaped Airframe. By Carl Gerhold And, Carl H. Gerhold and Lorenzo R. Clark. Abstract. Scientific and technical findings by NASA-sponsored contractors and grantees.

CONFERENCE PUBLICATION. Collected papers from scientific and technical conferences, symposia, seminars, or other meetings.

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 : Lorenzo R.

Clark and Carl H. Gerhold. A previous study by Clark and Gerhold on an early model of the BWB concept airframe verified significant shielding of the inlet-radiated noise by the fuselage.

In addition to verifying inlet noise shielding, the data were to be used to validate an analytical model. Initial comparison of measured to estimated noise shielding was by: Spatially distributed models of broadband turbomachinery and jet exhaust noise for engine source breakdown processing of phased array measurements Validation of the Predicted Circumferential and Radial Mode Sound Power Levels in the Inlet and Exhaust Ducts of a Fan Ingesting Distorted Inflow.

Lisa Koch; Airframe-Noise Reduction by. Database of inlet and exhaust noise shielding for wedge-shaped airframe (OCoLC) Online version: Gerhold Carl H. Database of inlet and exhaust noise shielding for wedge-shaped airframe (OCoLC) Material Type: Government publication, National government publication, Internet resource: Document Type: Book, Internet Resource.

The design of future low-noise aircraft will require an account of noise shielding as a fundamental design parameter. This aspect was already recognized in The current low-noise aircraft design concepts of the hybrid-wing-body type require establishing a new knowledge base to allow an assessment of their potential noise : Karl-Stéphane Rossignol, Jan Werner Delfs, Michael Mößner, Markus Lummer, Jianping Yin.

Inlet noise reduction by shielding for the blended-wing-body airplane. Numerical Simulation of Engine Noise Shielding around Blended Wing Body Aircraft. TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, Vol. 58, No. Hybrid Wing–Body Aircraft Slat Noise.

Intake and exhaust orifice noise contributes to interior and exterior vehicle noise. The order noise radiated from the orifice of the intake and exhaust systems is caused by the pressure pulses generated by the periodic charging and discharging process and propagates to the open ends of the duct systems.

This study is motivated by the development of ultra-quiet advent aircraft that use jet noise shielding by the airframe. Current methods to predict shielding from aircraft surfaces rely on formulae. Gerhold and L.

Clark, “ Database of inlet and exhaust noise shielding for wedge-shaped airframe,” NASA/TM, NASA (). Google Scholar; A.

Savitzky and M. Golay, “ Smoothing and differentiation of data by simplified least squares procedures,” Anal. Cited by: 4. Noise shielding for aircraft Approach Take~-off FIG.

Noise footprint. As mentioned above, noise shielding may consid- erably alter the shape of a footprint, and it may be that the time will come when noise requirements are expressed in terms of the size and shape of footprints rather than EPNL values at three specified by: The Calculation of Acoustic Shielding of Engine Noise by the Silent Aircraft Airframe Acoustic shielding estimates of noise from engines placed above a wing have been obtained by a few investigators in the past, experimentally and numerically, for both tube-and-wing and °ying-wing aircraft.

APPLICATION: EXHAUST SOUND DESIGN 3 CYLINDER HIGH PERFORMANCE ENGINE ORIFICE NOISE APPROACH Development of a dominant/sporty exhaust orifice noise Boundary conditions Pass-by noise limit Exhaust system back pressure Active orifice noise attenuation Approach Excitation from engine dyno measurement.

noise and thermal transmittal A quick and easy to fit system of semi-rigid ducting that can result in up to 70% time saving during the on-site installation process, compared to rigid or spiral duct methods. This innovative system uses low resistance and antibacterial smooth round and oval tubes which connect.

Noise Criteria (NC) is a single number rating derived from sound pressure levels in all eight octave bands, and is intended to predict an occupant’s response to the overall sound level. The critical octave bands for evaluating sound performance ranges from 63 to Size: 1MB.Engine noise sources considered were fan inlet noise with duct treatment, fan exhaust noise with duct treatment, combustor or “core” noise, and jet noise.

Turbine noise was neglected since its levels are usually well below the other sources. Airframe noise sources of the BWB were not modeled.Database of Inlet and Exhaust Noise Shielding for Wedge-Shaped Airframe. Apr 1, 04/ by Gerhold, Carl H.; Clark 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.