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Journal ArticleDOI

Behaviour of trailing wing(s) in echelon formation due to wing twist and aspect ratio

01 Apr 2017-Aerospace Science and Technology (Elsevier Masson)-Vol. 63, pp 294-303
TL;DR: In this article, the effect of both geometric and aerodynamic twist on the induced drag of individual lifting surfaces in configuration flight including post-stall angles of attack has been investigated using a vortex lattice method.
About: This article is published in Aerospace Science and Technology.The article was published on 2017-04-01. It has received 8 citations till now. The article focuses on the topics: Wing twist & Lift-induced drag.
Citations
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Journal ArticleDOI
TL;DR: A systematic procedure of high-precision parameterization and multi-objective optimization for airfoils was proposed in this paper in order to improve the aerodynamic performance under full working conditions.

23 citations

Journal ArticleDOI
TL;DR: Investigation of aerodynamic performance improvements of formation flight at transonic speeds for a medium size Unmanned Aerial Vehicle and empirical parametric analysis suggests that formation flight can improves aerodynamics performance and formation configuration greatly influence the degree of improvement.
Abstract: This paper investigates aerodynamic performance improvements of formation flight at transonic speeds for a medium size Unmanned Aerial Vehicle (UAV). The metric for assessing the aerodynamic improvement of formation flight is the computed drag. The total drag for each formation configuration is compared with a single UAV, where a final drag reduction percentage is estimated. The evaluation of the aerodynamic performance is conducted by employing an in-house Computational Fluid Dynamics (CFD) solver, grid generation and post processing tools. For critical understanding of the tendency of the formation efficiency depending on main parameters, broad formation configurations are analysed. The parameterisation includes number of aircraft, proximity and formation shape. Full realisation of the benefit predicted would need to be proven in the real world, but there is sufficient confidence to suggest that it exist: the empirical parametric analysis suggests that formation flight can improves aerodynamic performance and formation configuration greatly influence the degree of improvement.

9 citations


Cites result from "Behaviour of trailing wing(s) in ec..."

  • ...There have been also recent studies undertaken to find an optimum spacing between the various units in formation and some studies cased light upon the effect of shape and size of the leader and follower [8, 9]....

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Journal ArticleDOI
TL;DR: In this article, a composite pre/post (ACP) module was used to establish the static analysis of the wing, and two improvement schemes were proposed to deal with the problem that the wing with high aspect ratio would encounter.
Abstract: Wings with large aspect ratio have large bending moment and torque, so the poor flexural and torsional stiffness are noteworthy. The application of composite materials in wing structure can improve the performance of wing. In the design process of the wing with high aspect ratio, the design parameters of the wing are preliminarily set. Then, the wing configuration is determined according to the force characteristics referring to the indexes of the Predator unmanned aerial vehicle (UAV), and on the basis of the composite material mechanics and finite element theory, the finite element model of the wing is designed as well. Next, we carry out the aerodynamic analysis in FLUENT. At last, we use ANSYS Composite Pre/Post (ACP) module to establish the static analysis of the wing, and two improvement schemes are proposed to deal with the problem that the wing with high aspect ratio would encounter.

8 citations

Journal ArticleDOI
15 Jun 2018
TL;DR: In this paper, a multi-fidelity computational framework for the analysis of aerodynamic performance of flight formation is presented, based on the Vortex Lattice and Reynolds Averaged Navier-Stokes methods.
Abstract: This paper introduces a multi-fidelity computational framework for the analysis of aerodynamic performance of flight formation. The Vortex Lattice and Reynolds Averaged Navier–Stokes methods form the basis of the framework, as low- and high-fidelity, respectively. Initially, the computational framework is validated for an isolated wing, and then two rectangular NACA23012 wings are considered for assessing the aerodynamic performance of this formation; the optimal relative position is through the multi-fidelity framework based on the total drag reduction. The performance estimates are in good agreement with experimental measurements of the same configuration. Total aerodynamic performance of formation flight is also assessed with respect to attitude variations of the lifting bodies involved. The framework is also employed to determine the optimal position of blended-wing-body unmanned aerial vehicles in tandem formation flight.

6 citations

01 Jan 2004
TL;DR: A novel scheme is presented for an iterative decambering approach to predict the post-stall characteristics of wings using known section data as inputs to be more robust at achieving convergence.
Abstract: RINKU MUKHERJEE. Post-Stall Prediction of Multiple-Lifting-Surface Configurations Using a Decambering Approach. (Under the direction of Dr. Ashok Gopalarathnam.) A novel scheme is presented for an iterative decambering approach to predict the post-stall characteristics of wings using known section data as inputs. The new scheme differs from earlier ones in the details of how the residual in the Newton iteration is computed. With earlier schemes, multiple solutions are obtained for wings at high angles of attack as the final converged solution depends on the initial conditions used for the iteration. With this scheme, multiple solutions at high angles of attack are brought to light right during the computation of the residuals for the Newton iteration. In general, the new scheme is found to be more robust at achieving convergence. Experimental validation is provided using experimental airfoil lift curves from Naik and Ostowari for three different aspect ratios of rectangular wings. Results are presented from a study of the stall characteristics of wings of different planform shapes and two configurations of a wing-tail and a wing-canard configuration. Results are also presented from a study to investigate possible asymmetric lift distributions when the iterations were started with an initial asymmetric distribution of the decambering. Post-Stall Prediction of Multiple-Lifting-Surface Configurations Using a Decambering Approach

3 citations

References
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01 Jan 1989
TL;DR: This paper presents a list of recommended recipes for making CDRom decks and some examples of how these recipes can be modified to suit theommelier's needs.
Abstract: Keywords: informatique ; numerical recipes Note: contient un CDRom Reference Record created on 2004-09-07, modified on 2016-08-08

4,920 citations


"Behaviour of trailing wing(s) in ec..." refers methods in this paper

  • ...A 2N X 2N matrix equation has to be solved for each step of the Newton iteration [18], as shown in Eq....

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Book ChapterDOI
01 Jan 1989
TL;DR: In this article, an inviscid linear-vorticity panel method with a Karman-Tsien compressiblity correction is developed for direct and mixed-inverse modes.
Abstract: Calculation procedures for viscous/inviscid analysis and mixed-inverse design of subcritical airfoils are presented. An inviscid linear-vorticity panel method with a Karman-Tsien compressiblity correction is developed for direct and mixed-inverse modes. Source distributions superimposed on the airfoil and wake permit modeling of viscous layer influence on the potential flow. A two-equation lagged dissipation integral method is used to represent the viscous layers. Both laminar and turbulent layers are treated, with an e 9-type amplification formulation determinining the transition point. The boundary layer and transition equations are solved simultaneously with the inviscid flowfield by a global Newton method. The procedure is especially suitable for rapid analysis of low Reynolds number airfoil flows with transitional separation bubbles. Surface pressure distributions and entire polars are calculated and compared with experimental data. Design procedure examples are also presented.

2,185 citations


Additional excerpts

  • ...The input 2D airfoil data (Cl–α and Cm–α) of NACA0012 at Re = 1 × 106 is obtained from XFoil [19]....

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  • ...In the present work, 2D data of NACA0012 airfoil from XFoil at Re = 1 × 106 is used to predict 3D post-stall data using geometric twist for a single wing and compared with literature....

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01 Jan 1959
TL;DR: Chang et al. as discussed by the authors proposed a new geometric analysis procedure for wing sections based on the normal mode analysis for continuous functions, which can be used to calculate the section length.
Abstract: The thin airfoil theory for calculation of section ... http://charles-oneill.com/projects/iaf.pdf Thin Airfoil Theory Charles R. O’Neill ... The objective is to review the thin airfoil theory and to apply the theory to three wing sections. THEORY OF WINGS AND WIND TUNNEL TESTING OF A NACA 2415 AIRFOIL http://www.ewp.rpi.edu/hartford/~ernesto/F2011/EP/MaterialsforStudents/Ferrari/Ghods2001.PDF 2.0 STRUCTURE AND THEORY OF WINGS Wing is an aerodynamic structure that generates lift when comes into contact with moving air molecules i.e. wind. tbausyd.wikispaces.com http://tbausyd.wikispaces.com/file/view/aerodynamics_report1.3.doc Abbot & von Doenhoff, 1959, 'Theory of Wing Sections – including a summary of airfoil data', Dover Edition, Dover Publications, New York. Geometric Analysis of Wing Sections RITA | National ... http://ntl.bts.gov/lib/1000/1200/1265/950049_chang.pdf GEOMETRIC ANALYSIS OF WING SECTIONS I-Chung Chang, Francisco J. Torres, and Chee Tung? Ames Research Center SUMMARY This paper describes a new geometric analysis ... Geometric Analysis of Wing Sections NASA http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19950018209_1995118209.pdf This paper describes a new geometric analysis procedure for wing sections. This procedure is based on the normal mode analysis for continuous functions. 4. Incompressible Potential Flow Virginia Tech http://www.dept.aoe.vt.edu/~mason/Mason_f/C4WHMPanels.doc

1,956 citations

Book
01 Jan 1991
TL;DR: In this article, the authors present a general solution of the Incompressible, Potential Flow Equations over three-dimensional airfoils, with complex variables. But they do not specify the exact solutions with complex variables.
Abstract: Introduction and Background. Fundamentals of Inviscid, Incompressible Flow. General Solution of the Incompressible, Potential Flow Equations. Small Disturbance Flow Over Three Dimensional Airfoils. Exact Solutions with Complex Variables. Perturbation Methods. Three-Dimensional Small Disturbance Solutions. Numerical (Panel) Methods. Singularity Elements and Influence Coefficients. Two-Dimensional Numerical Solutions. Three-Dimensional Numerical solutions. Unsteady Aerodynamics. Advanced Topics. Airfoil Integrals. Singularity Distribution Integrals. Principle Value of the Lifting Surface Integral. Sample Computer Programs.

612 citations


"Behaviour of trailing wing(s) in ec..." refers methods in this paper

  • ...The effects of δ1 and δ2 on the change in Cl and Cm for a given α can be computed reasonably well using thin airfoil theory and a three-term Fourier series approximation for a flat plate with a flap deflection [17]....

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