A Multidisciplinary Analysis of Tail Buffeting Alleviation Using Streamwise Fences

A multidisciplinary analysis of vertical tail buffeting and buffeting alleviation of generic fighter aircraft is conducted. This complex multidisciplinary problem is solved for the fluid dynamics, structure dynamics, fluid-structure coupling, and grid deformation using a computing environment that controls the temporal synchronization of the data transfer between the analysis modules. The generic fighter aircraft consists of a sharp-edged delta wing with an aspect ratio of one and a swept-back, flexible, vertical twin tail with a taper ratio of 0.23. Twin streamwise fences are located at the 30% chord-station of the delta wing. The fences are used to alter the vortical flow and to delay the onset of vortex breakdown above the delta wing, in order to alleviate the twin-tail buffeting. The effect of the geometrical shape of the fences on the buffeting responses is investigated. The performance of the fences over a wide range of high angles of attack is also investigated. The trapezoidal configuration of the fences at a taper ratio of 0.7 produced the most favorable results. The results indicated that the fences are effective in reducing the aeroelastic loads and responses, especially at angles of attack less than 30°.

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Aerodynamic characteristics of delta wing–body combinations at high angles of attack

The Aeronautical Journal ◽

10.1017/s0001924000049848 ◽

1994 ◽

Vol 98 (975) ◽

pp. 159-170 ◽

Cited By ~ 1

Author(s):

P. R. Viswanath ◽

S. R. Patil

Keyword(s):

Vortex Breakdown ◽

Delta Wing ◽

Aerodynamic Characteristics ◽

Surface Flow ◽

Flow Visualisation ◽

Symmetric Flow ◽

Gradual Process ◽

Wing Sweep ◽

The Mean ◽

High Angles Of Attack

AbstractAn experimental study investigating the aerodynamic characteristics of generic delta wing-body combinations up to high angles of attack was carried out at a subsonic Mach number. Three delta wings having sharp leading edges and sweep angles of 50°, 60° and 70° were tested with two forebody configurations providing a variation of the nose fineness ratio. Measurements made included six-component forces and moments, limited static pressures on the wing lee-side and surface flow visualisation studies. The results showed symmetric flow features up to an incidence of about 25°, beyond which significant asymmetry was evident due to wing vortex breakdown, forebody vortex asymmetry or both. At higher incidence, varying degrees of forebody-wing vortex interaction effects were seen in the mean loads, which depended on the wing sweep and the nose fineness ratio. The vortex breakdown on these wings was found to be a gradual process, as implied by the wing pressures and the mean aerodynamic loads. Effects of forebody vortex asymmetry on the wing-body aerodynamics have also been assessed. Comparison of Datcom estimates with experimental data of longitudinal aerodynamic characteristics on all three wing-body combinations indicated good agreement in the symmetric flow regime.

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Detached-Eddy Simulations and Reynolds-Averaged Navier-Stokes Simulations of Delta Wing Vortical Flowfields

Journal of Fluids Engineering ◽

10.1115/1.1517570 ◽

2002 ◽

Vol 124 (4) ◽

pp. 924-932 ◽

Cited By ~ 46

Author(s):

Scott Morton ◽

James Forsythe ◽

Anthony Mitchell ◽

David Hajek

Keyword(s):

Vortex Breakdown ◽

Delta Wing ◽

Turbulence Models ◽

Reynolds Numbers ◽

Navier Stokes ◽

Detached Eddy Simulation ◽

Fighter Aircraft ◽

Eddy Simulation ◽

Reynolds Averaged Navier Stokes ◽

High Reynolds

An understanding of vortical structures and vortex breakdown is essential for the development of highly maneuverable vehicles and high angle of attack flight. This is primarily due to the physical limits these phenomena impose on aircraft and missiles at extreme flight conditions. Demands for more maneuverable air vehicles have pushed the limits of current CFD methods in the high Reynolds number regime. Simulation methods must be able to accurately describe the unsteady, vortical flowfields associated with fighter aircraft at Reynolds numbers more representative of full-scale vehicles. It is the goal of this paper to demonstrate the ability of detached-eddy Simulation (DES), a hybrid Reynolds-averaged Navier-Stokes (RANS)/large-eddy Simulation (LES) method, to accurately predict vortex breakdown at Reynolds numbers above 1×106. Detailed experiments performed at Onera are used to compare simulations utilizing both RANS and DES turbulence models.

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Aerodynamic Analysis of a Supersonic Transport Aircraft at Landing Speed Conditions

Energies ◽

10.3390/en14206615 ◽

2021 ◽

Vol 14 (20) ◽

pp. 6615

Author(s):

Andrea Aprovitola ◽

Pasquale Emanuele Di Nuzzo ◽

Giuseppe Pezzella ◽

Antonio Viviani

Keyword(s):

High Speed ◽

Cfd Simulation ◽

Vortex Breakdown ◽

Delta Wing ◽

Research Effort ◽

Static Stability ◽

Commercial Aviation ◽

Supersonic Flight ◽

Supersonic Transport ◽

Wide Range

Supersonic flight for commercial aviation is gaining a renewed interest, especially for business aviation, which demands the reduction of flight times for transcontinental routes. So far, the promise of civil supersonic flight has only been afforded by the Concorde and Tupolev T-144 aircraft. However, little or nothing can be found about the aerodynamics of these aeroshapes, the knowledge of which is extremely interesting to obtain before the development of the next-generation high-speed aircraft. Therefore, the present research effort aimed at filling in the lack of data on a Concorde-like aeroshape by focusing on evaluating the aerodynamics of a complete aircraft configuration under low-speed conditions, close to those of the approach and landing phase. In this framework, the present paper focuses on the CFD study of the longitudinal aerodynamics of a Concorde-like, tailless, delta-ogee wing seamlessly integrated onto a Sears–Haack body fuselage, suitable for civil transportation. The drag polar at a Mach number equal to 0.24 at a 30 m altitude was computed for a wide range of angles of attack (0∘,60∘), with a steady RANS simulation to provide the feedback of the aerodynamic behaviour post breakdown, useful for a preliminary design. The vortex-lift contribution to the aerodynamic coefficients was accounted for in the longitudinal flight condition. The results were in agreement with the analytical theory of the delta-wing. Flowfield sensitivity to the angle of attack at near-stall and post-stall flight attitudes confirmed the literature results. Furthermore, the longitudinal static stability was addressed. The CFD simulation also evidenced a static instability condition arising for 15∘≤α≤20∘ due to vortex breakdown, which was accounted for.

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Recent developments in delta wing aerodynamics

The Aeronautical Journal ◽

10.1017/s0001924000000269 ◽

2004 ◽

Vol 108 (1087) ◽

pp. 437-452 ◽

Cited By ~ 46

Author(s):

I. Gursul

Keyword(s):

Shear Layer ◽

Vortex Breakdown ◽

Delta Wing ◽

Layer Structure ◽

Vortical Flow ◽

Time Lags ◽

Delta Wings ◽

Vortex Interactions ◽

Recent Developments ◽

Wing Aerodynamics

Abstract Recent developments in delta wing aerodynamics are reviewed. For slender delta wings, recent investigations shed more light on the unsteady aspects of shear-layer structure, vortex core, breakdown and its instabilities. For nonslender delta wings, substantial differences in the structure of vortical flow and breakdown may exist. Vortex interactions are generic to both slender and nonslender wings. Various unsteady flow phenomena may cause buffeting of wings and fins, however, vortex breakdown, vortex shedding, and shear layer reattachment are the most dominant sources. Dynamic response of vortex breakdown over delta wings in unsteady flows can be characterised by large time lags and hysteresis, whose physical mechanisms need further studies. Unusual flow–structure interactions for nonslender wings in the form of self-excited roll oscillations have been observed. Recent experiments showed that substantial lift enhancement is possible on a flexible delta wing.

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APPLICATION OF AN EULER SOLVER TO SELECTED PROBLEMS IN FLIGHT DYNAMICS

Aviation ◽

10.3846/16487788.2007.9635956 ◽

2007 ◽

Vol 11 (2) ◽

pp. 13-22

Author(s):

Janusz Sznajder ◽

Jerzy Zółtak

Keyword(s):

Unsteady Flow ◽

Steady Flow ◽

Vortex Breakdown ◽

Delta Wing ◽

Flow Analysis ◽

Vortical Flow ◽

Flow Equations ◽

Euler Solver ◽

Unsteady Flow Analysis

Several applications of a Euler solver with the formulation of the flow equations in the noninertial reference system with steady and unsteady flow analysis are presented. The steady‐flow applications include determination of aerodynamic derivatives with respect to angular velocity and analysis of vortical flow over a delta wing at high angles of attack with the determination of aerodynamic coefficients and analysis of vortex breakdown. The unsteady flow analysis is applied in the simulation of a rapid manoeuvre for the determination of unsteady forces. The results of this simulation are compared with results of simulations using steady‐flow approximation in order to assess the advantages of unsteady flow analysis in the simulation of aircraft manoeuvres.

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