Vibration reduction of helicopter with trailing-edge flaps at various flying conditions

Kodakkattu, SK; Joy, M. L.; Nair, K. Prabhakaran

doi:10.1177/0954410016642460

Cited by 6 publications

(3 citation statements)

References 34 publications

(41 reference statements)

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“…Kodakkattu et al. 12 used a three-level orthogonal array design with three design variables to create second-order polynomial response surface functions to approximate the hub vibration and flap power objective functions in the design optimization of a helicopter rotor blade. Reynolds et al.…”

Section: Literature Surveymentioning

confidence: 99%

Design optimization of a shell and tube heat exchanger with staggered baffles using neural network and genetic algorithm

Saijal

Thondiyil

2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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A shell and tube heat exchanger with staggered baffles (STHX-ST) is designed by integrating the features of both segmental and helical baffles, which produces a helical flow in the shell side. This work studies the effect of different parameters on the performance of the STHX-ST through numerical analysis. Shell inner diameter, tube outer diameter, baffle cut, baffle spacing, and baffle orientation angle are the design parameters. Multi-objective optimization using genetic algorithm (GA) is carried out to maximize the heat transfer rate while minimizing the pressure drop. The objective functions for optimization are approximated using artificial neural networks (ANNs). The training data for ANNs are simulated from CFD analysis as per the Taguchi orthogonal test table. The optimal solution obtained from the Pareto front has a maximum heat transfer of 154555 W for a minimum pressure drop of 88083.86 Pa.

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Section: Literature Surveymentioning

confidence: 99%

Design optimization of a shell and tube heat exchanger with staggered baffles using neural network and genetic algorithm

Saijal

Thondiyil

2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…10,11 Compared with the length of the blade, the maximum radius of the hub is much smaller, 12,13 which makes the linear velocity on the surface of the hub much smaller than other parts of the blade, so the hub is usually ignored when calculating the aerodynamic characteristics of the rotor. 14,15 But in fact, there are many parts and linkage mechanisms in the center of the rotor, which is very unfavorable for radar stealth, 5,10 while the reasonable design of the hub can well shield the incident waves from the outside.…”

Section: Introductionmentioning

confidence: 99%

Blunt hub affecting the radar cross section of rotor based on dynamic scattering method

Zhou

Huang

Chen

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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In order to study the radar characteristics of blunt-hub rotor, a dynamic scattering method (DSM) based on physical optics and physical theory of diffraction is presented. Important influencing factors are analyzed and discussed, including rotor disk inclination, azimuth, elevation angle, and radar wave frequency. The radar cross section (RCS) of the blunt-hub rotor is used for comparison with conventional-hub rotor and sharp-hub rotor. The RCS performance of the blunt-hub rotor at different radar wave frequencies is close to that of the sharp-hub rotor. At larger positive elevation angles, the RCS∼azimuth performance of the blunt-hub rotor is not as good as the other two rotors, while the RCS performance of the blunt-hub rotor has an advantage under the larger negative elevation angle and the inclination of the rotor disk. The presented DSM is feasible and effective for learning the electromagnetic scattering characteristics of the blunt-hub rotor.

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“…(2015) investigated combined action of the trailing-edge flap and variable-stiffness devices, which were located at the pitch link and at the blade root, to alleviate helicopter main rotor vibratory hub loads. Kodakkattu et al . (2017) attempted to find the optimal torsional stiffness and trailing-edge flap location for minimum vibration and flap control power.…”

Section: Introductionmentioning

confidence: 99%

Design improvements and flap deflection evaluations with considering centrifugal load on active trailing edge flap

Visconti

Eun

Sim

et al. 2018

AEAT

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Purpose The purpose of this paper is to present the design, analysis and experiments of the active trailing-edge flap (Seoul National University Flap, SNUF) for vibration reduction in the helicopter rotor prior to the small-scale blades planned to test in a whirl tower. Design/methodology/approach The predictions of the hinge moment in both steady and unsteady flows were obtained through computational fluid dynamics calculations. When compared with the results originated from analytical formulations, the proposed method showed improved prediction capabilities. To validate the deflection of the flap under the centrifugal load by rotating, static analysis was conducted using both contact and rotating condition of MSC NASTRAN. The corresponding experiment also was performed using the vertical frame for simulating the effect of the centrifugal force. Findings The hinge moment of the flap is predicted through unsteady analysis in the actuation frequency of 3/rev. The material of the guide in the flap mechanism was selected through static analysis under both contact and rotating condition. Finally, reduction of the deflection occurred because of the load in the axial direction of the hinge like the centrifugal load. Practical implications The important aspects, such as design, analysis, and experiments for the active trailing-edge flap were shown. Originality/value This paper showed the relationship of the displacement, block force and voltage of the piezo-actuator, combined with the hinge moment predicted. The methodology and the experiment were presented for simulating the centrifugal force acting on the flap.

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Vibration reduction of helicopter with trailing-edge flaps at various flying conditions

Cited by 6 publications

References 34 publications

Design optimization of a shell and tube heat exchanger with staggered baffles using neural network and genetic algorithm

Design optimization of a shell and tube heat exchanger with staggered baffles using neural network and genetic algorithm

Blunt hub affecting the radar cross section of rotor based on dynamic scattering method

Design improvements and flap deflection evaluations with considering centrifugal load on active trailing edge flap

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