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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 wing‐in‐ground 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 wing‐in‐ground 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

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 paper is…

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

Keywords

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 (WIG) effect

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

Keywords

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

Keywords

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.

1273

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

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, namely…

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

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 the…

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

Article
Publication date: 10 May 2013

Wang Hao, CJ Teo, BC Khoo and CJ Goh

The potential increase in aerodynamic efficiency whilst operating in close proximity to the ground has stimulated substantial interests in the design and applications of…

Abstract

Purpose of paper

The potential increase in aerodynamic efficiency whilst operating in close proximity to the ground has stimulated substantial interests in the design and applications of Wing‐In‐Ground (WIG) craft. The purpose of this paper is to investigate the aerodynamic and stability characteristics, such as the Aerodynamic Center of Height (ACH) and the Aerodynamic Center of Pitch (ACP) of a NACA4412 airfoil in ground effect and give clear physical and mathematical definitions of ACH and ACP

Design/methodology/approach

Both a panel method and a Finite Volume Method (FVM) have been employed to analyze the aerodynamic and stability characteristics numerically in this paper.

Findings

It is found that for the range of heights and pitch angles investigated, ACH of a NACA 4412 airfoil is only a function of pitch angle while ACP is only a function of height. The ACH of a NACA4412 airfoil lies behind the ACP. When viscous effects are taken into account, the ACH of the NACA4412 airfoil moves further forwards due to boundary layer de‐cambering effects.

Originality/value

These findings are important for preliminary WIG‐craft design and analysis in term of airfoil selection.

Details

International Journal of Intelligent Unmanned Systems, vol. 1 no. 2
Type: Research Article
ISSN: 2049-6427

Keywords

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, in…

1156

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

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 a…

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. 95 no. 4
Type: Research Article
ISSN: 1748-8842

Keywords

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