Interior noise considerations for advanced high-speed turboprop aircraft

Mixson, J. S.; Farassat, F.; Leatherwood, J. D.; Prydz, R. A.; Revell, J. D.

doi:10.2514/3.44944

Cited by 3 publications

(2 citation statements)

References 11 publications

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“…Historically, large propeller-driven commercial aircraft for passenger transport have been equipped with wing-mounted tractor propellers. For these aircraft, the highest sound pressure levels on the fuselage outer surface fall within 30 deg from the propeller rotation plane [17,32,33]. The distribution of the overall sound pressure level inside the cabin is less concentrated because of various transmission mechanisms [30,34], and the highest interior noise level is typically located approximately one diameter downstream of the propeller rotation plane, near the wing-fuselage junction [25,30,34].…”

Section: Nomenclaturementioning

confidence: 99%

Aerodynamic Performance and Static Stability Characteristics of Aircraft with Tail-Mounted Propellers

Arnhem

Vries

Sinnige

et al. 2022

Journal of Aircraft

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Section: Nomenclaturementioning

confidence: 99%

Aerodynamic Performance and Static Stability Characteristics of Aircraft with Tail-Mounted Propellers

Arnhem

Vries

Sinnige

et al. 2022

Journal of Aircraft

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“…Theoretical methods have been developed that predict the noise generated by high-speed propellers 1 ' 2 and experiments have been performed to verify these prediction methods as well as to examine the distribution of the exterior sound field on the fuselage surface. 2 ' 3 The transmission of noise through various types of aircraft panels has been studied analytically and experimentally. 4 " 9 Recently, some research has been undertaken to better understand the noise that is transmitted and reradiated into the cabin by way of structureborne vibrations.…”

Section: Introductionmentioning

confidence: 99%

Effects of acoustic treatment on the interior noise of a twin-enginepropeller airplane

Beyer

Powell

Daniels

et al. 1985

Journal of Aircraft

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A study of the cabin acoustics of a Fairchild Merlin IVC twin-engine propeller airplane is described^ The sound field was measured at six locations inside both an untreated "green" airplane and a completely finished airplane. Several flight conditions were tested, including different altitudes, engine power settings, and cabin pressures. The overall sound pressure level for each test condition and microphone position was computed from a one-third octave band analysis of the data. The blade passage frequency and its integral multiples, which dominate the low-frequency noise spectrum, were examined using a narrowband analysis of the data. The insertion loss due to the added acoustical treatment was determined by comparing the narrowband results from the two airplanes. These insertion loss values varied widely, depending on many factors, such as position in the cabin, multiple of blade passage frequency, cabin pressure, and engine torque. The space-averaged sound pressure levels corresponding to specific tests of the treated airplane were found to be in good agreement with predictions from the Propeller Aircraft Interior Noise (PAIN) computer program.

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Open Rotor Noise Prediction Methods at NASA Langley: A Technology Review

Farassat

Dunn²,

Tinetti³

et al. 2009

15th AIAA/CEAS Aeroacoustics Conference (30th AIAA Aeroacoustics Conference)

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Open rotors are once again under consideration for propulsion of the future airliners because of their high efficiency. The noise generated by these propulsion systems must meet the stringent noise standards of today to reduce community impact. In this paper we review the open rotor noise prediction methods available at NASA Langley. We discuss three codes called ASSPIN (Advanced Subsonic-Supersonic Propeller Induced Noise), FW H pds (Ffowcs Williams-Hawkings with penetrable data surface) and the FSC (Fast Scattering Code). The first two codes are in the time domain and the third code is a frequency domain code. The capabilities of these codes and the input data requirements as well as the output data are presented. Plans for further improvements of these codes are discussed. In particular, a method based on equivalent sources is outlined to get rid of spurious signals in the FW H pds code.https://ntrs.nasa.gov/search.jsp?R=20090020657 2018-05-10T21:55:46+00:00Z 1-IntroductionThe high fuel prices of recent years have caused the operating cost of the airlines to soar. In an effort to bring down the fuel consumption, the major aircraft engine manufacturers such as GE, Rolls-Royce and CFM International are now taking a fresh look at open rotors for the propulsion of future airliners. Open rotors, also known as propfans or unducted fans, can offer up to 30 per cent improvement in efficiency compared to high bypass engines of 1980 vintage currently in use in most civilian aircraft. The lower fuel consumption of open rotors also contributes to the reduction of carbon emission into the atmosphere by airliners. Open rotor propulsion system can, therefore, be considered a Green engine. The single and contra-rotating open rotors are both under consideration for powering future aircraft. An example of a contra-rotating open rotor is shown in Figure 1 below. Figure 1-An example of contra-rotating open rotor design by GEOpen rotors operate at transonic to supersonic helical tip speeds that can go as high as Mach 1.3. The noise of these propulsion systems can cause both passenger and community concerns. The ability to predict the noise of open rotors at the design stage and to reduce the noise to an acceptable level are, therefore, of great importance to engine manufacturers. In 1980s, a comprehensive study of open rotors by NASA and the U.S. aircraft engine industry was carried out involving theory development, model and full scale tests. An impressive array of technology development in aeroelasticity, composite materials, mechanical design, aerodynamics and aeroacoustics resulted from this study. A large number of technical reports and publications in open literature were written by the engineers and researchers involved in this effort. These reports and publications are of great value to those involved in the resurgence of interest in open rotors around the world. NASA Langley researchers have contributed significantly to the development of aeroacoustic technology of open rotors. The present authors feel that it is...

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Interior noise considerations for advanced high-speed turboprop aircraft

Cited by 3 publications

References 11 publications

Aerodynamic Performance and Static Stability Characteristics of Aircraft with Tail-Mounted Propellers

Aerodynamic Performance and Static Stability Characteristics of Aircraft with Tail-Mounted Propellers

Effects of acoustic treatment on the interior noise of a twin-enginepropeller airplane

Open Rotor Noise Prediction Methods at NASA Langley: A Technology Review

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