The Low-Noise Potential of Distributed Propulsion on a Catamaran Aircraft

Posey, Joe W.; Tinetti, Ana F.; Dunn, M. H.

doi:10.2514/6.2006-2622

Cited by 14 publications

(4 citation statements)

References 10 publications

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“…These complexities must be embedded within the liner's acoustic impedance Z and create a large possible parametric dependence to capture these effects, as discussed in the survey by Motsinger & Kraft (1995), creating a complex modelling challenge. Proposed future applications of acoustic liners to aircraft exteriors will further increase the parametric range required of impedance models (Posey, Tinetti & Dunn 2006).…”

mentioning

confidence: 99%

Numerical investigation of a honeycomb liner grazed by laminar and turbulent boundary layers

Zhang

Bodony

2016

J. Fluid Mech.

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Direct numerical simulations are used to study the interaction of a cavity-backed circular orifice with grazing laminar and turbulent boundary layers and incident sound waves. The flow conditions and geometry are representative of single degree-of-freedom acoustic liners applied in the inlet and exhaust ducts of aircraft engines and are the same as those from experiments conducted at NASA Langley. The simulations identify the fluid mechanics of how the sound field and state of the grazing boundary layer impact the in-orifice flow and suggest a simple flow analogy that enables scaling estimates. From the scaling estimates the simulations are then used to develop reduced-order models for the in-orifice flow and a time-domain impedance model is constructed. The liner is found to increase drag at all conditions studied by an amount that increases with the incident sound pressure amplitude.

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mentioning

confidence: 99%

Numerical investigation of a honeycomb liner grazed by laminar and turbulent boundary layers

Zhang

Bodony

2016

J. Fluid Mech.

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“…The flexibility offered by DEP systems permits placing the propulsors over the airframe in such a way to enhance noise shielding effects. Posey et al [94] achieved low-frequency noise reductions of the order of 20 dB across a significant community area. For turbo-electric distributed propulsion systems-i.e., when the electric power is provided by a common turbine-an effective by-pass ratio can be defined as the ratio of mass flow rate of all combined airflows to the one that enters the turbine.…”

Section: Noise Mitigation For Dep Systemsmentioning

confidence: 99%

The Enabling Technologies for a Quasi-Zero Emissions Commuter Aircraft

et al. 2022

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The desire for greener aircraft pushes both academic and industrial research into developing technologies, manufacturing, and operational strategies providing emissions abatement. At time of writing, there are no certified electric aircraft for passengers’ transport. This is due to the requirements of lightness, reliability, safety, comfort, and operational capability of the fast air transport, which are not completely met by the state-of-the-art technology. Recent studies have shown that new aero-propulsive technologies do not provide significant fuel burn reduction, unless the operational ranges are limited to short regional routes or the electric storage capability is unrealistically high, and that this little advantage comes at increased gross weight and operational costs. Therefore, a significant impact into aviation emissions reduction can only be obtained with a revolutionary design, which integrates disruptive technologies starting from the preliminary design phase. This paper reviews the recent advances in propulsions, aerodynamics, and structures to present the enabling technologies for a low emissions aircraft, with a focus on the commuter category. In fact, it is the opinion of the European Community, which has financed several projects, that advances on the small air transport will be a fundamental step to assess the results and pave the way for large greener airplanes.

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“…An additional advantage of retaining flexibility in the placement of propulsors is the ability to leverage noise shielding of wing-body surfaces or noise-reducing effects of boundary-layer ingestion [6,69]. For example, Posey et al [70] leveraged a DP system on a twin-fuselage platform and projected a low-frequency (f ≤ 320 Hz) reduction in noise of 20 dB across large community areas. A similar noise shielding approach was utilized in the development of the Quiet Short-Haul Research Aircraft vehicle developed by NASA [71][72][73][74][75].…”

Section: Distributed Electric Propulsion Enabled Noise Reductionmentioning

confidence: 99%

A Review of Distributed Electric Propulsion Concepts for Air Vehicle Technology

Kim

Perry

Ansell

2018

2018 AIAA/IEEE Electric Aircraft Technologies Symposium

232

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The emergence of distributed electric propulsion (DEP) concepts for aircraft systems has enabled new capabilities in the overall efficiency, capabilities, and robustness of future air vehicles. Distributed electric propulsion systems feature the novel approach of utilizing electrically-driven propulsors which are only connected electrically to energy sources or power-generating devices. As a result, propulsors can be placed, sized, and operated with greater flexibility to leverage the synergistic benefits of aero-propulsive coupling and provide improved performance over more traditional designs. A number of conventional aircraft concepts that utilize distributed electric propulsion have been developed, along with various short and vertical takeoff and landing platforms. Careful integration of electrically-driven propulsors for boundary-layer ingestion can allow for improved propulsive efficiency and wake-filling benefits. The placement and configuration of propulsors can also be used to mitigate the trailing vortex system of a lifting surface or leverage increases in dynamic pressure across blown surfaces for increased lift performance. Additionally, the thrust stream of distributed electric propulsors can be utilized to enable new capabilities in vehicle control, including reducing requirements for traditional control surfaces and increasing tolerance of the vehicle control system to engine-out or propulsor-out scenarios. If one or more turboelectric generators and multiple electric fans are used, the increased effective bypass ratio of the whole propulsion system can also enable lower community noise during takeoff and landing segments of flight and higher propulsive efficiency at all conditions. Furthermore, the small propulsors of a DEP system can be installed to leverage an acoustic shielding effect by the airframe, which can further reduce noise signatures. The rapid growth in flight-weight electrical systems and power architectures has provided new enabling technologies for future DEP concepts, which provide flexible operational capabilities far beyond those of current systems. While a number of integration challenges exist, DEP is a disruptive concept that can lead to unprecedented improvements in future aircraft designs.

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The Low-Noise Potential of Distributed Propulsion on a Catamaran Aircraft

Cited by 14 publications

References 10 publications

Numerical investigation of a honeycomb liner grazed by laminar and turbulent boundary layers

Numerical investigation of a honeycomb liner grazed by laminar and turbulent boundary layers

The Enabling Technologies for a Quasi-Zero Emissions Commuter Aircraft

A Review of Distributed Electric Propulsion Concepts for Air Vehicle Technology

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