Flight and Ground Operations in Support of Airframe Noise Reduction Tests

Baumann, Ethan; Waggoner, Erin R.

doi:10.2514/6.2018-2970

Cited by 8 publications

(9 citation statements)

References 11 publications

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“…The primary G-III used during the first and second tests was the SubsoniC Research Aircraft Testbed (SCRAT), also known by its tail number as "804" (see Fig. 1a) [12]. The 804 is a heavily instrumented testbed that allows many of the aircraft critical parameters, including its global position, angle of attack (AOA), and true airspeed (TAS) to be recorded during flight.…”

Section: Test Aircraft and Test Sitementioning

confidence: 99%

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Flight-Test Evaluation of Airframe Noise Mitigation Technologies

Khorrami

Lockard

Humphreys

et al. 2018

2018 AIAA/CEAS Aeroacoustics Conference

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A series of flight tests targeting airframe noise reduction was planned and executed under the NASA Flight Demonstrations and Capabilities project. The objectives of the tests were two-fold: to evaluate the aeroacoustic performance of several noise reduction technologies in a relevant environment and to generate a comprehensive database for advancing the state of the art in simulation-based airframe noise prediction methodologies. These technologiesan Adaptive Compliant Trailing Edge flap, main landing gear fairings, and gear cavity treatmentswere integrated on a NASA Gulfstream G-III aircraft to determine their effectiveness, both on a component-level (individually) and a system-level (combined) basis.With the aircraft flying an approach pattern and the engines set at ground idle, extensive acoustic measurements were acquired using a phased microphone array system. Detailed analyses of the gathered acoustic data clearly demonstrate that significant noise reduction was achieved for the flap and main landing gear components.

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Section: Test Aircraft and Test Sitementioning

confidence: 99%

“…The second G-III aircraft (called by its tail number "808") used to acquire acoustic data was flown in its original Fowler flap configuration (see Fig. 1b) [12]. Except for a NovAtel GPS receiver, the 808 had no other research instrumentation onboard to provide key aircraft parameters such as AOA and TAS.…”

Section: Test Aircraft and Test Sitementioning

confidence: 99%

Flight-Test Evaluation of Airframe Noise Mitigation Technologies

Khorrami

Lockard

Humphreys

et al. 2018

2018 AIAA/CEAS Aeroacoustics Conference

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“…The model developed for the present simulations is a full-scale, full-span, high-fidelity representation of the SCRAT aircraft with ACTE flaps installed [7]. The model comprises a fuselage, wing, ACTE flaps, flow-through nacelles including an engine hush kit, pylon, and main landing gear.…”

Section: Aircraft Configuration and Flight Conditionsmentioning

confidence: 99%

“…As an indispensable element of the flight test campaign, the high-fidelity simulations were used in two ways. First, they were essential during tailoring and retrofitting of the gear fairings into the main landing gear of the NASA Armstrong Flight Research Center (AFRC) SubsoniC Research Aircraft Testbed (SCRAT) [7], a Gulfstream G-III business jet. The fairings, which were originally developed for testing on the larger Gulfstream G-V aircraft, had to undergo significant design alterations in order to fit into the smaller and more compact G-III main landing gear [7] [8].…”

Section: Introductionmentioning

confidence: 99%

“…First, they were essential during tailoring and retrofitting of the gear fairings into the main landing gear of the NASA Armstrong Flight Research Center (AFRC) SubsoniC Research Aircraft Testbed (SCRAT) [7], a Gulfstream G-III business jet. The fairings, which were originally developed for testing on the larger Gulfstream G-V aircraft, had to undergo significant design alterations in order to fit into the smaller and more compact G-III main landing gear [7] [8]. During this initial stage, after each major design change was completed, the aeroacoustic performance of the redesigned fairings was evaluated via simulations of the full-scale landing gear installed on a semispan model of the G-III aircraft to ensure that the noise reduction effectiveness of the fairings was not seriously compromised.…”

Section: Introductionmentioning

confidence: 99%

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Simulations of a Full-Scale Aircraft with Installed Airframe Noise Reduction Technologies

Ferris¹,

Appelbaum²,

Khorrami

2018

2018 AIAA/CEAS Aeroacoustics Conference

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Computational results are presented for a high-fidelity, full-scale, full-span Gulfstream G-III aircraft model equipped with flap and main landing gear (MLG) noise reduction technologies. The simulations, which were conducted in support of a NASA airframe noise flight test campaign of the same technologies, use the lattice Boltzmann solver PowerFLOW ® to capture time-accurate flow data with sound propagation to the far field accomplished using a Ffowcs-Williams and Hawkings (FWH) acoustic analogy approach. The aerodynamic and aeroacoustic behavior of the aircraft were investigated in the approach configuration with combinations of flap and landing gear deployments. The simulated flap concept is an Adaptive Compliant Trailing Edge (ACTE) flap that replaces the Fowler flap system on the G-III aircraft. The simulated MLG noise reduction concept is comprised of porous fairings and a collection of other smaller fairings fitted around the flow-facing components. Using the Fowler flap results as a reference, comparisons are presented on the noise reduction effectiveness of the ACTE flap system. Investigations were made on the effects of using the porous fairings and ACTE flap as noise reduction concepts in tandem. The ACTE flap was found to reduce the total airframe noise level at all flap deflection angles when compared to the Fowler flap equipped model. As anticipated, a reduction in aerodynamic performance was also found when the ACTE flap system was used. The MLG fairings were shown to further reduce the total airframe noise level of the G-III.

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Aeroacoustic and aerodynamic characteristics of a morphing airfoil

Kan

Zhao

et al. 2021

AEAT

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Purpose This paper aims to assess the aeroacoustic and aerodynamic performance of a morphing airfoil with a flexible trailing edge (FTE). The objective is to make a comparison of the aerodynamic noise characteristics between the conventional airfoil with a flap and morphing airfoil and analyse the noise reduction mechanisms of the morphing airfoil. Design/methodology/approach The computational fluid dynamic method was used to calculate the aerodynamic coefficients of morphing airfoil and the Ffowcs-Williams and Hawking’s acoustic analogy methods were performed to predict the far-field noise of different airfoils. Findings Results show that compared with the conventional airfoil, the morphing airfoil can generate higher lift and lower noise, but a greater drag. Additionally, the noise caused by the one-unit lift of the morphing airfoil is significantly lower than that of the conventional airfoil. For the morphing airfoil, the shedding vortex in the trailing edge was the main noise resource. As the angle of attack (AoA) increases, the overall sound pressure level of the morphing airfoil increases significantly. With the increase of the trailing edge deflection angle, the amplitude and the period of sound pressure of the morning airfoil fluctuation increase. Practical implications Presented results could be very useful during designing the morphing airfoil with FTE, which has significant advantages in aerodynamic efficiency and aeroacoustic performance. Originality/value This paper presents the aerodynamic and aeroacoustic characteristics of the morphing airfoil. The effect of trailing edge deflection angle and AoA on morphing airfoil was investigated. In the future, using a morphing airfoil instead of a traditional flap can reduce the aircraft`s fuel consumption and noise pollution.

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Flight and Ground Operations in Support of Airframe Noise Reduction Tests

Cited by 8 publications

References 11 publications

Flight-Test Evaluation of Airframe Noise Mitigation Technologies

Flight-Test Evaluation of Airframe Noise Mitigation Technologies

Simulations of a Full-Scale Aircraft with Installed Airframe Noise Reduction Technologies

Aeroacoustic and aerodynamic characteristics of a morphing airfoil

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