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Article
Publication date: 13 July 2021

Mustafa Serdar Genç, Hacımurat Demir, Mustafa Özden and Tuna Murat Bodur

The purpose of this exhaustive experimental study is to investigate the fluid-structure interaction in the flexible membrane wings over a range of angles of attack for…

Abstract

Purpose

The purpose of this exhaustive experimental study is to investigate the fluid-structure interaction in the flexible membrane wings over a range of angles of attack for various Reynolds numbers.

Design/methodology/approach

In this paper, an experimental study on fluid-structure interaction of flexible membrane wings was presented at Reynolds numbers of 2.5 × 104, 5 × 104 and 7.5 × 104. In the experimental studies, flow visualization, velocity and deformation measurements for flexible membrane wings were performed by the smoke-wire technique, multichannel constant temperature anemometer and digital image correlation system, respectively. All experimental results were combined and fluid-structure interaction was discussed.

Findings

In the flexible wings with the higher aspect ratio, higher vibration modes were noticed because the leading-edge separation was dominant at lower angles of attack. As both Reynolds number and the aspect ratio increased, the maximum membrane deformations increased and the vibrations became visible, secondary vibration modes were observed with growing the leading-edge vortices at moderate angles of attack. Moreover, in the graphs of the spectral analysis of the membrane displacement and the velocity; the dominant frequencies coincided because of the interaction of the flow over the wings and the membrane deformations.

Originality/value

Unlike available literature, obtained results were presented comparatively using the sketches of the smoke-wire photographs with deformation measurement or turbulence statistics from the velocity measurements. In this study, fluid-structure interaction and leading-edge vortices of membrane wings were investigated in detail with increasing both Reynolds number and the aspect ratio.

Details

Aircraft Engineering and Aerospace Technology, vol. 93 no. 6
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 5 January 2015

Adnan Maqsood and Tiauw Hiong Go

The purpose of this paper is to describe the research performed on flexible-wing micro air vehicle (MAV). Typical attributes associated with the aerodynamics of MAVs are…

Abstract

Purpose

The purpose of this paper is to describe the research performed on flexible-wing micro air vehicle (MAV). Typical attributes associated with the aerodynamics of MAVs are low Reynolds number, low altitude flying environments and low aspect ratio platforms. These attributes give birth to several challenges such as poor aerodynamic performance, nonlinear lift patterns and reduced gust tolerance. Flexible-wing MAV is renowned for improved aerodynamic characteristics such as smooth flight in gusty conditions than its rigid-wing counterpart.

Design/methodology/approach

The wind-tunnel experiments are carried out for various configurations to determine the ways of further enhancing lift. The baseline geometric description for all MAVs includes 15-cm box dimension and an aspect ratio of 1. The experimental results of the baseline configuration are compared with other experimental results available in literature. After due validation, the effects of following parameters are quantized and compared with the rigid-wing counterpart: underlying skeleton; wing membrane extension; wing membrane relaxation; and wing membrane material (latex, silk, poly-vinyl chloride plastic sheet and nylon).

Findings

It is found that the skeleton layout significantly governs the lift characteristics. The effect of membrane extension and relaxation proved to be of little advantage. Latex sheets are found to be the best choice for membrane material. The aerodynamic assessment at low Reynolds number has demonstrated significant improvement of lift characteristics for flexible wings over rigid-wing counterparts.

Research limitations/implications

The results presented in this paper are based on wind-tunnel experimentation. Further experimentation through flight test may be needed to reveal the true aerodynamic performance under unsteady maneuvers.

Practical implications

The material properties vary significantly during fabrication. A technique to standardize the properties of flexible membranes is a missing link in literature and warrants further investigation.

Originality/value

This concept of flexible wing has shown high potential. The primary objective of this paper is to experimentally investigate ways of further enhancing the lift of flexible-wing MAVs by controlling flexibility passively. While various researchers have spent many years on developing the optimum wing frame for the flexible wing, research on different wing materials has been limited. This is the first paper of its kind covering all aspects of wing-frame design, material, effects of extension and relaxation on wing membrane.

Details

Aircraft Engineering and Aerospace Technology: An International Journal, vol. 87 no. 1
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 11 October 2019

Syam Narayanan S., Asad Ahmed R., Jijo Philip Varghese, Gopinath S., Jedidiah Paulraj and Muthukumar M.

The purpose of this paper is to experimentally analyze the effect of wing shape of various insects of different species in a flapping micro aerial vehicle (MAV).

Abstract

Purpose

The purpose of this paper is to experimentally analyze the effect of wing shape of various insects of different species in a flapping micro aerial vehicle (MAV).

Design/methodology/approach

Six different wings are fabricated for the MAV configuration, which is restricted to the size of 15 cm length and width; all wings have different surface area and constant span length of 6 cm. The force is being measured with the help of a force-sensing resistor (FSR), and the coefficients of lift were calculated and compared.

Findings

This study shows that the wing “Tipula sp” has better value of lift than other insect wings, except for the negative angle of attacks. The wing “Aeshna multicolor” gives the better values of lift in negative angles of attack.

Practical implications

This paper lays the foundation for the development of flapping MAVs with the insect wings. This type of wing can be used for spying purpose in the military zone and also can be used to survey remote and dangerous places where humans cannot enter.

Originality/value

This paper covers all basic insect wing configurations of different species with exact mimics of the veins. As the experimental investigation was carried for different angle of attacks, velocities and flapping frequencies, this paper can be used as reference for future flapping wing MAV developers.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 2
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 12 April 2011

Cheng Zou and Jihong Liu

Drilling is an important operation in aircraft wing assembly. In order to enhance this operation, automated machines are used. The purpose of this paper is to propose an…

Abstract

Purpose

Drilling is an important operation in aircraft wing assembly. In order to enhance this operation, automated machines are used. The purpose of this paper is to propose an off‐line programming system to generate NC code effectively and accurately for a five‐axis NC drilling machine applied in aircraft wing flexible assembly.

Design/methodology/approach

The NC program is divided into three hierarchical parts to correspond, respectively, to the whole wing, single rib and single hole. The programming procedure for such three‐layer wing structures is detailed, which includes product model modification, NC program generation and post‐processing.

Findings

By demonstration, the implemented system is proved to increase the efficiency and correctness of NC programming, and the generated program performed well on a flexible wing drilling system.

Research limitations/implications

The system can only program for automated drilling machine at present, however with further development both automated drilling and riveting machine in aircraft wing assembly can be programmed by this system. Another development might make this system universal for different machineries and other aircraft components.

Originality/value

The paper indicates a new way to program for rapid wing flexible drilling, and the generated NC program is more adaptable and easier to update for various aircraft wing structures.

Details

Assembly Automation, vol. 31 no. 2
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 31 August 2022

Mostafa Arasteh, Yegane Azargoon and M.H. Djavareshkian

Ground effect is one of the important factors in the enhancement of wing aerodynamic performance. This study aims to investigate the aerodynamic forces and performance of…

Abstract

Purpose

Ground effect is one of the important factors in the enhancement of wing aerodynamic performance. This study aims to investigate the aerodynamic forces and performance of a flapping wing with the bending deflection angel under the ground effect.

Design/methodology/approach

In this study, the wing and flapping mechanism were designed and manufactured based on the seagull flight and then assembled. It is worth noting that this mechanism is capable of wing bending in the upstroke flight as big birds. Finally, the model was examined at bending deflection angles of 0° and 107° and different distances from the surface, flapping frequencies and velocities in forward flight in a wind tunnel.

Findings

The results revealed that the aerodynamic performance of flapping wings in forward flight improved due to the ground effect. The effect of the bending deflection mechanism on lift generation was escalated when the flapping wing was close to the surface, where the maximum power loading occurred.

Practical implications

Flapping wings have many different applications, such as maintenance, traffic control, pollution monitoring, meteorology and high-risk operations. Unlike fixed-wing micro aerial vehicles, flapping wings are capable of operating in very-low Reynolds-number flow regimes. On the other hand, ground effect poses positive impacts on the provision of aerodynamic forces in the take-off process.

Originality/value

Bending deflection in the flapping motion and ground effect are two influential factors in the enhancement of the aerodynamic performance of flapping wings. The combined effects of these two factors have not been studied yet, which is addressed in this study.

Details

Aircraft Engineering and Aerospace Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 1 April 1954

E.G. Broadbent

IN Part I wc saw how structural flexibility could introduce aerodynamic forces which might eventually lead to instability, or to the complete nullification of a desired…

Abstract

IN Part I wc saw how structural flexibility could introduce aerodynamic forces which might eventually lead to instability, or to the complete nullification of a desired aerodynamic effect. The phenomenon of flutter presents another problem in stability, but in this case an oscillatory instability is threatened. It must be realized at the outset that flutter is no mere resonance phenomenon such as the bad vibrations a motor‐car may exhibit at a particular engine speed. Flutter is a vibration in which energy is extracted from the airstrcam to help build up the amplitude, and a catastrophic failure can easily occur within a second of the start of the flutter.

Details

Aircraft Engineering and Aerospace Technology, vol. 26 no. 4
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 6 September 2011

John Lee, Scott Newbern, Yu‐Chong Tai, Chih‐Ming Ho and Po‐Hao Adam Huang

The goal of this research is to demonstrate micro‐electro‐mechanical systems (MEMS)‐based transducers for aircraft maneuvering. Research in wind tunnels have shown that…

Abstract

Purpose

The goal of this research is to demonstrate micro‐electro‐mechanical systems (MEMS)‐based transducers for aircraft maneuvering. Research in wind tunnels have shown that micro‐actuators can be used to manipulate leading edge vortices found on aerodynamic surfaces with moderate to highly swept leading edges, such as a delta wing. This has been labeled as the MEMS vortex shift control (MEMS‐VSC). The work presented in this paper seeks to detail the evolution of real‐world flight tests of this research using remotely piloted vehicles (RPVs).

Design/methodology/approach

Four different RPVs were constructed and used for flight tests to demonstrate the ability of using MEMS devices to provide flight control, primarily in the rolling axis.

Findings

MEMS devices for high angle‐of‐attack (AOA) turning flights have been demonstrated and the paper finds that the success of a complex project like the MEMS‐VSC requires the marriage of basic science expertise found in academia and the technical expertise found in industry.

Research limitations/implications

Owing to the need to test fly the RPVs at low altitudes for video documentation while performing high AOA maneuvers, the attrition of the RPVs becomes the dominant factor to the pace of research.

Practical implications

MEMS sensors and actuators can be used to augment flight control at high AOA, where conventional control surfaces typically experiences reduced effectiveness. Separately, the lessons learned from the integration efforts of this research provide a potentially near parallel case study to the development of ornithopter‐based micro aerial vehicles.

Originality/value

This is the only research‐to‐date involving the demonstration of the MEMS‐VSC on real‐world flight vehicles.

Details

Aircraft Engineering and Aerospace Technology, vol. 83 no. 5
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 17 November 2021

Rohollah Dehghani Firouz-Abadi and Mohammad Reza Borhan Panah

The purpose of this paper is to analyze the stability of aeroelastic systems using a novel reduced order aeroelastic model.

Abstract

Purpose

The purpose of this paper is to analyze the stability of aeroelastic systems using a novel reduced order aeroelastic model.

Design/methodology/approach

The proposed aeroelastic model is a reduced-order model constructed based on the aerodynamic model identification using the generalized aerodynamic force response and the unsteady boundary element method in various excitation frequency values. Due to the low computational cost and acceptable accuracy of the boundary element method, this method is selected to determine the unsteady time response of the aerodynamic model. Regarding the structural model, the elastic mode shapes of the shell are used.

Findings

Three case studies are investigated by the proposed model. In the first place, a typical two-dimensional section is introduced as a means of verification by approximating the Theodorsen function. As the second test case, the flutter speed of Advisory Group for Aerospace Research and Development 445.6 wing with 45° sweep angle is determined and compared with the experimental test results in the literature. Finally, a complete aircraft is considered to demonstrate the capability of the proposed model in handling complex configurations.

Originality/value

The paper introduces an algorithm to construct an aeroelastic model applicable to any unsteady aerodynamic model including experimental models and modal structural models in the implicit and reduced order form. In other words, the main advantage of the proposed method, further to its simplicity and low computational effort, which can be used as a means of real-time aeroelastic simulation, is its ability to provide aerodynamic and structural models in implicit and reduced order forms.

Details

Aircraft Engineering and Aerospace Technology, vol. 94 no. 3
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 18 May 2015

Hongwei Ma, Yueri Cai, Yuliang Wang, Shusheng Bi and Zhao Gong

The paper aims to develop a cownose ray-inspired robotic fish which can be propelled by oscillating and chordwise twisting pectoral fins.

Abstract

Purpose

The paper aims to develop a cownose ray-inspired robotic fish which can be propelled by oscillating and chordwise twisting pectoral fins.

Design/methodology/approach

The bionic pectoral fin which can simultaneously realize the combination of oscillating motion and chordwise twisting motion is designed based on analyzing the movement of cownose ray’s pectoral fins. The structural design and control system construction of the robotic fish are presented. Finally, a series of swimming experiments are carried out to verify the effectiveness of the design for the bionic pectoral fin.

Findings

The experimental results show that the deformation of the bionic pectoral fin can be well close to that of the cownose ray’s. The bionic pectoral fin can produce effective angle of attack, and the thrust generated can propel robotic fish effectively. Furthermore, the tests of swimming performance in the water tank show that the robotic fish can achieve a maximum forward speed of 0.43 m/s (0.94 times of body length per second) and an excellent turning maneuverability with a small radius.

Originality/value

The oscillating and pitching motion can be obtained simultaneously by the active control of chordwise twisting motion of the bionic pectoral fin, which can better imitate the movement of cownose ray’s pectoral fin. The designed bionic pectoral fin can provide an experimental platform for further study of the effect of the spanwise and chordwise flexibility on propulsion performance.

Details

Industrial Robot: An International Journal, vol. 42 no. 3
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 7 January 2022

Syam Narayanan S. and Asad Ahmed R.

The purpose of this study is to experimentally analyse the effect of flexible and stiffened membrane wings in the lift generation of flapping micro air vehicle (MAV).

Abstract

Purpose

The purpose of this study is to experimentally analyse the effect of flexible and stiffened membrane wings in the lift generation of flapping micro air vehicle (MAV).

Design/methodology/approach

This is analysed by the rectangle wing made up of polyethylene terephthalate sheets of 100 microns. MAV is tested for the free stream velocity of 2 m/s, 4 m/s, 6 m/s and k* of 0, 0.25, 1, 3, 8. This test is repeated for flapping MAV of the free flapping frequency of 2 Hz, 4 Hz, 6 Hz, 10 Hz and 12 Hz.

Findings

This study shows that the membrane wing with proper stiffeners can give better lift generation capacity than a flexible wing.

Research limitations/implications

Only a normal force component is measured, which is perpendicular to the longitudinal axis of the model.

Practical implications

In MAVs, the wing structures are thin and light, so the effect of fluid-structure interactions is important at low Reynold’s numbers. This data are useful for the MAV developments.

Originality/value

The effect of chord-wise flexibility in lift generation is the study of the effect of a flexible wing and rigid wing in MAV. It is analysed by the rectangle wing. The coefficient of normal force at different free stream conditions was analysed.

Details

Aircraft Engineering and Aerospace Technology, vol. 94 no. 5
Type: Research Article
ISSN: 1748-8842

Keywords

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