Optimization by CFD analyses of riblet distribution over a transonic civil aircraft configuration

Restrictions of emissions for civil aircraft engines, on the one hand, and the need in increasing the engine efficiency, on the other hand, cause difficulties during development of low-emission combustors for such engines.

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Design of electromagnetic hazard protection of civil aircraft

10.3403/03011757u ◽

2015 ◽

Keyword(s):

Civil Aircraft

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Metrological aspects of pre-flight anti-icing procedures for civil aircraft

The world of measurement ◽

10.35400/1813-8667-2019-3-22-26 ◽

2019 ◽

pp. 22-26

Author(s):

А. Богоявленский ◽

A. Bogoyavlenskiy

Keyword(s):

Negative Impact ◽

Landing Gear ◽

Flight Performance ◽

Spray Nozzle ◽

Subsequent Formation ◽

Inlet Guide Vanes ◽

Civil Aircraft ◽

Engine Compressor ◽

Temperature And Pressure ◽

Instrumental Control

Snow-ice deposits formed on the outer surfaces of aircrafts on the ground during parking can have a negative impact during take-off due to the deterioration of aerodynamic and flight performance, a significant and even critical decrease in lift, increased drag, blocking controls, difficulty or blocking of landing gear retraction, damage to the blades of inlet guide vanes and/or the blades of an engine compressor. To exclude the influence of snow and ice deposits, anti-icing treatment is performed, including their removal and/or protection from subsequent formation. For this purpose, special anti-icing machines (deicers), equipped with such means of instrumental control as counters of anti-icing fluid pumps, measuring scales of anti-icing fluid tanks, thermometers and pressure gauges for temperature and pressure measuring at the outlet of a spray nozzle, are used. The article deals with the metrological aspects of civil aircrafts anti-icing prior to flight.

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Yaw Galloping of a TLWP Platform Under High Speed Currents by Analytical Methods and its Comparison With Experimental Results

Volume 1: Offshore Technology ◽

10.1115/omae2017-61909 ◽

2017 ◽

Author(s):

Francisco Lamas ◽

Miguel A. M. Ramirez ◽

Antonio Carlos Fernandes

Keyword(s):

High Speed ◽

Production Systems ◽

Experimental Tests ◽

Experimental Results ◽

Analytical Methodology ◽

New Approach ◽

Laboratory Facilities ◽

Polynomial Curve ◽

Computational Fluid Dynamics Cfd ◽

Cfd Analyses

Flow Induced Motions are always an important subject during both design and operational phases of an offshore platform life. These motions could significantly affect the performance of the platform, including its mooring and oil production systems. These kind of analyses are performed using basically two different approaches: experimental tests with reduced models and, more recently, with Computational Fluid Dynamics (CFD) dynamic analysis. The main objective of this work is to present a new approach, based on an analytical methodology using static CFD analyses to estimate the response on yaw motions of a Tension Leg Wellhead Platform on one of the several types of motions that can be classified as flow-induced motions, known as galloping. The first step is to review the equations that govern the yaw motions of an ocean platform when subjected to currents from different angles of attack. The yaw moment coefficients will be obtained using CFD steady-state analysis, on which the yaw moments will be calculated for several angles of attack, placed around the central angle where the analysis is being carried out. Having the force coefficients plotted against the angle values, we can adjust a polynomial curve around each analysis point in order to evaluate the amplitude of the yaw motion using a limit cycle approach. Other properties of the system which are flow-dependent, such as damping and added mass, will also be estimated using CFD. The last part of this work consists in comparing the analytical results with experimental results obtained at the LOC/COPPE-UFRJ laboratory facilities.

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Design of a Variable-Stiffness Compliant Skin for a Morphing Leading Edge

Applied Sciences ◽

10.3390/app11073165 ◽

2021 ◽

Vol 11 (7) ◽

pp. 3165

Author(s):

Zhigang Wang ◽

Yu Yang

Keyword(s):

Composite Laminate ◽

Large Scale ◽

Design Method ◽

Leading Edge ◽

Variable Stiffness ◽

Manufacturing Constraints ◽

Aircraft Wing ◽

Noise Abatement ◽

Civil Aircraft ◽

Final Profile

A seamless and smooth morphing leading edge has remarkable potential for noise abatement and drag reduction of civil aircraft. Variable-stiffness compliant skin based on tailored composite laminate is a concept with great potential for morphing leading edge, but the currently proposed methods have difficulty in taking the manufacturing constraints or layup sequence into account during the optimization process. This paper proposes an innovative two-step design method for a variable-stiffness compliant skin of a morphing leading edge, which includes layup optimization and layup adjustment. The combination of these two steps can not only improve the deformation accuracy of the final profile of the compliant skin but also easily and effectively determine the layup sequence of the composite layup. With the design framework, an optimization model is created for a variable-stiffness compliant skin, and an adjustment method for its layups is presented. Finally, the deformed profiles between the directly optimized layups and the adjusted ones are compared to verify its morphing ability and accuracy. The final results demonstrate that the obtained deforming ability and accuracy are suitable for a large-scale aircraft wing.

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