Characterization of atmospheric turbulence as a function of altitude

Prasad, Suparnamaaya; Ivanco, Marie L.; Ivanco, Thomas G.; Ancel, Ersin

doi:10.2514/6.2017-3064

Cited by 2 publications

(3 citation statements)

References 6 publications

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“…A companion paper documents the methodology and results of an investigation of atmospheric turbulence as a function of altitude and the projected sensitivity of the AARSC shape-change concept. 13 This study concluded that the probability of moderate to severe turbulence encounters is lower at cruise altitudes of 20,000 feet by comparison to typical cruise altitudes of 35,000 feet. Furthermore, the response of the shape change concept to a unit gust is several factors less than the response of conventional aircraft, such as the DC-6, at the same altitude due to design parameters that include wing loading, cruise velocity, and gross weight.…”

Section: E Susceptibility To Turbulencementioning

confidence: 77%

Aerodynamically-Actuated Radical Shape-Change Concept

Ivanco

Ancel

et al. 2017

17th AIAA Aviation Technology, Integration, and Operations Conference

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Aerodynamically-actuated radical shape change (AARSC) is a novel concept that enables flight vehicles to conduct a mission profile containing radically different flight regimes while possibly mitigating the typical penalties incurred by radical geometric change. Weight penalties are mitigated by utilizing a primary flight control to generate aerodynamic loads that then drive a shape-change actuation. The flight mission profile used to analyze the AARSC concept is that of a transport aircraft that cruises at a lower altitude than typical transports. Based upon a preliminary analysis, substantial fuel savings are realized for mission ranges below 2000 NM by comparison to a state-of-the-art baseline, with an increasing impact as mission range is reduced. The predicted savings are so significant at short-haul ranges that the shape-change concept rivals the fuel-burn performance of turboprop aircraft while completing missions in less time than typical jet aicraft. Lower-altitude cruise has also been sought after in recent years for environmental benefits, however, the performance penalty to conventional aircraft was prohibitive. AARSC may enable the opportunity to realize the environmental benefits of lower-altitude emissions coupled with mission fuel savings. The findings of this study also reveal that the AARSC concept appears to be controllable, turbulence susceptibility is likely not an issue, and the shape change concept appears to be mechanically and aerodynamically feasible. Nomenclature AARSC = Aerodynamically Actuated Radical Shape Change CAT = Clear Air Turbulence DARPA = Defense Advanced Research Projects Agency q = Dynamic pressure (psf) Wact = Weight penalty factor for wing actuation

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Section: E Susceptibility To Turbulencementioning

confidence: 77%

Aerodynamically-Actuated Radical Shape-Change Concept

Ivanco

Ancel

et al. 2017

17th AIAA Aviation Technology, Integration, and Operations Conference

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“…After obtaining the vertical gust (V gust ), as well as the true airspeed (TAS = V ∞ ), lift coefficient (C L ), air density ( ρ), and aircraft characteristics such as the weight (W) and wing area (S), the load factor variation may be calculated (7).…”

Section: Methodsmentioning

confidence: 99%

“…Some research tries to identify turbulence areas from the eddy dissipation rate (EDR) or other turbulence indicators, as well as using detection and simulation programmes [1][2][3][4][5][6]. Additionally, much research has been based on the observation of these turbulences and on detecting the conditions under which they occur [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Additional Clearance over Obstacles to Determine Minimum Flight Altitude in Mountainous Terrain

Pérez Sanz,

Fernández-Shaw González,

Pérez-Castán

et al. 2024

Applied Sciences

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The International Civil Aviation Organization (ICAO) specifies that in the design phase of instrument flight procedures, an additional clearance may be added to an obstacle when flights are over mountainous terrain. This clearance increase can be up to 100 per cent of the minimum obstacle clearance (MOC). Airspace and instrument flight procedure designers usually face the problem of determining what value should be applied, since setting the maximum value of 100% often implies operational penalties, but there are no standardized criteria to determine lower values. The ICAO PANS-OPS indicates that the additional clearance over obstacles in mountainous areas is caused by two effects, both related to orography and wind speed. The first effect is due to the altimeter indication error. The second one is related to the loss of altitude when an aircraft is exposed to turbulence produced by mountain waves. This paper presents a methodology for determining the additional clearance to be applied over obstacles when, in the flight procedure design phase, the overflight of mountainous terrain is expected. Through this methodology, results have been achieved for the proposal of an appropriate additional clearance. The development of graphs and tables allows us to identify which additional value should be considered in each case.

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Characterization of atmospheric turbulence as a function of altitude

Cited by 2 publications

References 6 publications

Aerodynamically-Actuated Radical Shape-Change Concept

Aerodynamically-Actuated Radical Shape-Change Concept

Additional Clearance over Obstacles to Determine Minimum Flight Altitude in Mountainous Terrain

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