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Article
Publication date: 20 January 2012

Yang Wei and Yang Zhigang

The purpose of this paper is to investigate the aerodynamics of wing in ground effect with tiltable endplates for a new type winginground effect (WIG) craft.

Abstract

Purpose

The purpose of this paper is to investigate the aerodynamics of wing in ground effect with tiltable endplates for a new type winginground effect (WIG) craft.

Design/methodology/approach

The concept of tiltable endplates was implemented into the design of a WIG craft. Numerical investigation on aerodynamics of the tiltable endplate was carried out. The endplate effect on aerodynamics was deeply investigated with a rectangular wing at given angle of attack and flight height. The size of endplate relative to whole wing was then studied based on given endplate deflection angle and flight height. Finally, aerodynamics and flow of tiltable endplate in various flight heights and endplate deflection angles were analyzed. Aerodynamics, pressure and wingtip vortex were recorded in the study.

Findings

Endplate influences development of wingtip vortex and improves aerodynamics. Tiltable endplate can enable WIG craft to yield improved aerodynamic performance and worthwhile economy improvements on long‐distance flights in and out of ground effect (OGE).

Research limitations/implications

The results are entirely based on computational fluid dynamics (CFD). The gap between “numerical world” and “real world” depends on development and appropriate application of CFD. The current work shows further understanding of ground effect and aerodynamics of wing in ground effect.

Practical implications

The aerodynamics and aerodynamic optimization of wing in ground effect are of the great importance for WIG craft. The work improves the design and research on aerodynamics of WIG craft.

Originality/value

The concept of tiltable endplate for a new type wing in ground effect allows WIG craft to achieve good aerodynamic performance not only in ground effect but also in OGE. This was studied and proved in the current work.

Details

Aircraft Engineering and Aerospace Technology, vol. 84 no. 1
Type: Research Article
ISSN: 0002-2667

Keywords

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Article
Publication date: 4 January 2016

Mohammad Saeed Seif and Mohammad Tavakoli Dakhrabadi

The purpose of this paper is to present a fast, economical and practical method for mathematical modeling of aerodynamic characteristics of rectangular wing in ground

Abstract

Purpose

The purpose of this paper is to present a fast, economical and practical method for mathematical modeling of aerodynamic characteristics of rectangular wing in ground (WIG) effect.

Design/methodology/approach

Reynolds averaged Navier–Stokes (RANS) equations were converted to Bernoulli equation by reasonable assumptions. Also, Helmbold’s equation has been developed for calculation of the slope of wing lift coefficient in ground effect by defining equivalent aspect ratio (ARe). Comparison of present work results against the experimental results has shown good agreement.

Findings

A practical mathematical modeling with lower computational time and higher accuracy was presented for calculating aerodynamic characteristics of rectangular WIG effect. The relative error between the present work results and the experimental results was less than 8 per cent. Also, the accuracy of the proposed method was checked by comparing with the numerical methods. The comparison showed fairly good accuracy.

Research limitations/implications

Aerodynamic surfaces in ground effect were used for reducing wetted surface and increasing speed in high-speed marine and novel aeronautical vehicles.

Practical implications

The proposed method is useful for investigation of aerodynamic performance of WIG vehicles and racing boats with aerodynamic surfaces in ground effect.

Originality/value

The proposed method has reduced the computational time significantly as compared to numerical simulation that allows conceptual design of the WIG crafts and is also economical.

Details

Aircraft Engineering and Aerospace Technology: An International Journal, vol. 88 no. 1
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 3 January 2017

Mojtaba Tahani, Mehran Masdari and Ali Bargestan

This paper aims to investigate the aerodynamic characteristics as well as static stability of wing-in-ground effect aircraft. The effect of geometrical characteristics…

Abstract

Purpose

This paper aims to investigate the aerodynamic characteristics as well as static stability of wing-in-ground effect aircraft. The effect of geometrical characteristics, namely, twist angle, dihedral angle, sweep angle and taper ratio are examined.

Design/methodology/approach

A three-dimensional computational fluid dynamic code is developed to investigate the aerodynamic characteristics of the effect. The turbulent model is utilized for characterization of flow over wing surface.

Findings

The numerical results show that the maximum change of the drag coefficient depends on the angle of attack, twist angle and ground clearance, in a decreasing order. Also, it is found that the lift coefficient increases as the ground clearance, twist angle and dihedral angle decrease. On the other hand, the sweep angle does not have a significant effect on the lift coefficient for the considered wing section and Reynolds number. Also, as the aerodynamic characteristics increase, the taper ratio befits in trailing state.

Practical implications

To design an aircraft, the effect of each design parameter needs to be estimated. For this purpose, the sensitivity analysis is used. In this paper, the influence of all parameter against each other including ground clearance, angle of attack, twist angle, dihedral angle and sweep angle for the NACA 6409 are investigated.

Originality/value

As a summary, the contribution of this paper is to predict the aerodynamic performance for the cruise condition. In this study, the sensitivity of the design parameter on aerodynamic performance can be estimated and the effect of geometrical characteristics has been investigated in detail. Also, the best lift to drag coefficient for the NACA 6409 wing section specifies and two types of taper ratios in ground effect are compared.

Details

Aircraft Engineering and Aerospace Technology, vol. 89 no. 1
Type: Research Article
ISSN: 1748-8842

Keywords

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Article
Publication date: 14 June 2021

Mojtaba Tahani, Mehran Masdari and Ali Bargestan

The overall performance of an aerial vehicle strongly depends on the specifics of the propulsion system and its position relative to the other components. The purpose of…

Abstract

Purpose

The overall performance of an aerial vehicle strongly depends on the specifics of the propulsion system and its position relative to the other components. The purpose of paper is this factor can be characterized by changing several contributing parameters, such as distance from the ground, fuselage and wing as well as the nacelle outlet velocity and analyzing the aerodynamic performance.

Design/methodology/approach

Navier–Stokes equations are discretized in space using finite volume method. A KW-SST model is implemented to model the turbulence. The flow is assumed steady, single-phase, viscous, Newtonian and compressible. Accordingly, after validation and verification against experimental and numerical results of DLRF6 configuration, the location of the propulsion system relative to configuration body is examined.

Findings

At the nacelle outlet velocity of V/Vinf = 4, the optimal location identified in this study delivers 16% larger lift to drag ratio compared to the baseline configuration.

Practical implications

Altering the position of the propulsion system along the longitudinal direction does not have a noticeable effect on the vehicle performance.

Originality/value

Aerial vehicles including wing-in-ground effect vehicles require thrust to fly. Generating this necessary thrust for motion and acceleration is thoroughly affected by the vehicle aerodynamics. There is a lack of rigorous understanding of such topics owing to the immaturity of science in this area. Complexity and diversity of performance variables for a numerical solution and finding a logical connection between these parameters are among the related challenges.

Details

Aircraft Engineering and Aerospace Technology, vol. 93 no. 5
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 23 March 2010

D.W. Marshall, S.J. Newman and C.B. Williams

The purpose of this paper is to investigate the effect a variety of different boundary layers have on a wing in groundeffect.

Abstract

Purpose

The purpose of this paper is to investigate the effect a variety of different boundary layers have on a wing in groundeffect.

Design/methodology/approach

Experiments were carried out in the University of Southampton's 3′×2′ wind tunnel. A variable length splitter plate was designed and manufactured in order to generate four boundary‐layer thicknesses at a selected measurement position. A single element inverted GA(W)‐1 aerofoil was then introduced to the flow at varying heights above the plate. Laser Doppler anemometry (LDA) and surface static pressure measurements (both on the aerofoil surface and on the splitter plate) were recorded.

Findings

The flow beneath the wing is found to be affected considerably by the presence of the boundary layer. As the boundary‐layer thickness is increased, the under‐wing pressure is observed to increase, hence resulting in decreased suction. Further, the LDA results indicate a modification to the wake profile. In particular, at low wing heights, the wake is observed to become entrained in the boundary layer, to differing degrees dependant on the boundary layer present and the wing height.

Research limitations/implications

The acquisition of force values from the tests will have allowed further understanding of the “real world” implications of the presence of the boundary‐layer thicknesses on a wing in groundeffect but this is not possible in the test facility used.

Practical implications

The aerodynamics of a wing in groundeffect are of great interest for both lifting surfaces for aircraft and downforce generation in motorsport applications. The implications of this paper enhance the importance of understanding the boundary conditions present when wind tunnel testing for these applications.

Originality/value

Although the influence of the boundary layer on low ground clearance objects has been well documented, the methods used here, in particular the use of the pressure tapped splitter plate and LDA, allow a further insight into the explanations behind this influence.

Details

Aircraft Engineering and Aerospace Technology, vol. 82 no. 2
Type: Research Article
ISSN: 0002-2667

Keywords

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Article
Publication date: 6 August 2020

Hongwei Ma, Shuai Ren, Junxiang Wang, Hui Ren, Yang Liu and Shusheng Bi

This paper aims to carry out the research on the influence of ground effect on the performance of robotic fish propelled by oscillating paired pectoral fins.

Abstract

Purpose

This paper aims to carry out the research on the influence of ground effect on the performance of robotic fish propelled by oscillating paired pectoral fins.

Design/methodology/approach

The two-dimensional ground effect model of the oscillating pectoral fin without considering flexible deformation is established by introducing a two-dimensional fluid ground effect model. The parameters of the influence of ground effect on the oscillating pectoral fin are analyzed. Finally, the ground effect test platform is built, and a series of hydrodynamic experiments are carried out to study the influence of ground effect on the propulsion performance of the robotic fish propelled by oscillating paired pectoral fins under different motion parameters.

Findings

The thickness of the trailing edge and effective clearance are two important parameters that can change the influence of ground effect on the rigid pectoral fin. The experimental results are consistent with that obtained through theoretical analysis within a certain extent, which indicates that the developed two-dimensional ground effect model in this paper can be used to analyze the influence of ground effect on the propulsion performance of the oscillating pectoral fin. The experiment results show that the average thrust increases with the decreasing distance between the robot fish and the bottom. Meanwhile, with the increase of oscillation frequency and amplitude, the average thrust increases gradually.

Originality/value

The developed two-dimensional ground effect model provides the theoretical basis for the further research on the influence of ground effect on the propulsion performance of the oscillating pectoral fin. It can also be used in the design of the bionic pectoral fins.

Details

Industrial Robot: the international journal of robotics research and application, vol. 48 no. 1
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 23 March 2012

Jonathan W. Vogt and Tracie J. Barber

Investigations into ground effect phenomena about aerofoils are typically conducted on either an upright (lift‐producing) or inverted (downforce‐producing) configuration…

Abstract

Purpose

Investigations into ground effect phenomena about aerofoils are typically conducted on either an upright (lift‐producing) or inverted (downforce‐producing) configuration, in isolation. This limited approach does not promote a holistic understanding of how ground effect influences aerofoils. This paper aims to address this issue.

Design/methodology/approach

A two‐dimensional computational fluid dynamics investigation was conducted on the highly cambered Tyrrell aerofoil, in both its upright and inverted configurations, in order to better understand ground effect phenomena by observing how it influences each configuration differently. The trends in force and flow field behaviour were observed at various ground clearances through observation of the normal and drag forces and pressure coefficient plots. The aerofoil was held stationary and at a constant angle of attack of 6 degrees, with a moving ground plane to simulate the correct relative motion.

Findings

The different ground effect mechanisms that occur on each configuration are highlighted and explained. It is shown how ground effect manifests through these different phenomena and that there are general or overarching mechanisms that influence both configurations. These general mechanisms allow unintuitive phenomena, such as the downward movement of the stagnation point on both configurations, to be explained.

Originality/value

Overarching mechanisms of ground effect are discovered which are of value in any situation in which ground effect aerodynamics is to be exploited.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 22 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

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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

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Article
Publication date: 2 November 2015

Tien Phuc Dang, Zhengqi Gu and Zhen Chen

The purpose of this paper is to gain a better understanding of the flow field structure around the race car in two cases: stationary wheel and rotating wheel. In addition…

Abstract

Purpose

The purpose of this paper is to gain a better understanding of the flow field structure around the race car in two cases: stationary wheel and rotating wheel. In addition, this paper also illustrates and clarifies the influence of wheel rotation on the aerodynamic characteristics around the race car.

Design/methodology/approach

The author uses steady Reynolds-Averaged Navier-Stokes (RANS) equations with the Realizable k-ε model to study model open-wheel race car. Two cases are considered, a rotating wheel and stationary wheel.

Findings

The results obtained from the study are presented graphically, pressure, velocity distribution, the flow field structure, lift coefficient (Cl) and drag coefficient (Cd) for two cases and the significant influence of rotating case on flow field structure around wheel and aerodynamic characteristics of race car. The decreases in Cd and Cl values in the rotating case for the race car are 16.83 and 13.25 per cent, respectively, when compared to the stationary case.

Originality/value

Understanding the flow field structures and aerodynamic characteristics around the race car in two cases by the steady RANS equations with the Realizable k-ε turbulence model.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 25 no. 8
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 27 March 2019

Jafar Masri, Laurent Dala and Benoit Huard

This paper aims to investigate the different analytical methods used to predict the performance of seaplanes to define the weaknesses in each method and be able to extend…

Abstract

Purpose

This paper aims to investigate the different analytical methods used to predict the performance of seaplanes to define the weaknesses in each method and be able to extend the analytical approach to include the nonlinear terms (unsteadiness).

Design/methodology/approach

First, the elemental hydrodynamic characteristics of seaplanes are discussed. Second, five different analytical methods are reviewed. The advantages and disadvantages of each method are stated. After that, the heave and pitch equations of seaplane motion are illustrated. The procedure of obtaining the solution of the heave and pitch equations of seaplane motion is explained. Finally, the results obtained from the most common methods are compared.

Findings

The results show that the methods are based on different assumptions and considerations. As a result, no method is optimal for all types of seaplanes. Moreover, some of the analytical methods do not study the stability of the seaplane, which is a major issue in the design of seaplanes. In addition, all methods consider the motion as steady and linear. The objective is to extend the work to include the nonlinear effects.

Originality/value

This paper presents some of the analytical methods used in describing the performance of seaplanes and explains how can they be applied. Moreover, it summarises the advantages and disadvantages of each method.

Details

Aircraft Engineering and Aerospace Technology, vol. 91 no. 6
Type: Research Article
ISSN: 1748-8842

Keywords

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