| 1. |
- Cronander, C., et al.
(författare)
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Closed loop roll control using aeroelastic information
- 2000
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Ingår i: Aerospace Science and Technology. - 1270-9638 .- 1626-3219. ; 4:7, s. 481-494
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Tidskriftsartikel (refereegranskat)abstract
- A mathematical model of the rolling dynamics of a flexible wing is derived by experimental measurements and 3D potential flow analysis. Based on the mathematical model which includes one aeroelastic parameter, control laws are designed which almost completely eliminate the problem of reduced aileron efficiency for increasing airspeed. Finally, the control laws are tested on the model in the wind tunnel, and good correlation with computer simulations is achieved, except when a structural mode is excited.
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| 2. |
- Girodroux-Lavigne, P., et al.
(författare)
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Comparison of static and dynamic fluid-structure interaction solutions in the case of a highly flexible modern transport aircraft wing
- 2003
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Ingår i: Aerospace Science and Technology. - 1270-9638 .- 1626-3219. ; 7:2, s. 121-133
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the computational work performed by five of the fifteen partners in the Brite-Euram project UNSI, for the prediction of static aeroelastic configurations and dynamic flutter response at transonic conditions, using advanced time-domain fluid-structure coupling methods. The aerodynamic models, mechanical models, and coupling strategies implemented in the different solvers are presented. A code to code validation of the fluid-structure coupled solvers has been achieved in the case of the highly flexible MDO wing. The coupled codes have each been used first for the computation of steady state flow and static deformations at different flight conditions. The investigation of flutter has been carried out for off-design, heavy-cruise flight conditions, using time-consistent numerical simulations. Dynamic responses have been recorded and compared for stable and flutter conditions. © 2002 Éditions scientifiques et médicales Elsevier SAS. All rights reserved.
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| 3. |
- Haggmark, C. P., et al.
(författare)
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A numerical and experimental study of a transitional separation bubble
- 2001
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Ingår i: Aerospace Science and Technology. - 1270-9638 .- 1626-3219. ; 5:5, s. 317-328
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Tidskriftsartikel (refereegranskat)abstract
- A combined numerical and experimental study of a two-dimensional transitional separation bubble due to an adverse pressure gradient is reported. The experiments have been performed in the MTL wind tunnel with a contoured wall imposing an adverse pressure gradient on the flow over a flat plate. The separated shear-layer is highly unstable and transition to turbulence occurs in the flow. The experimental separation bubble flow is modelled numerically using two-dimensional direct numerical simulations (DNS). Prescribing free stream boundary conditions in the wall normal velocity the experimental bubble is reproduced. The development of artificially forced two-dimensional instability waves is investigated and good agreement is found between experiments, simulations and linear stability theory (LST). The performance of several engineering transition prediction methods applied on the present separation bubble is presented and compared. Methods based on simplifications of the e(n)-method yield predictions in accordance with experiments and DNS.
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| 4. |
- Young, T., et al.
(författare)
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Durability of hybrid laminar flow control (HLFC) surfaces
- 2003
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Ingår i: Aerospace Science and Technology. - 1270-9638 .- 1626-3219. ; 7:3, s. 181-190
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Tidskriftsartikel (refereegranskat)abstract
- As a part of the European Commission sponsored HYLTEC (Hybrid Laminar Flow Technology) project, a SAAB 2000 aircraft - fitted with a number of small laser drilled panels on the wing leading edge - completed 20 months of routine service, the objective being to investigate contamination and durability aspects of Hybrid Laminar Flow Control (HLFC) suction surfaces. A post-flight test investigation of these panels, manufactured from Nd-YAG laser drilled titanium, aluminium and carbon fibre polyetheretherketone (PEEK) composite, has been conducted. Using Scanning Electron Microscopy (SEM), evidence of corrosion and damage was investigated. An optical inspection technique was used to measure hole geometries and the results were compared to pressure loss measurements through the panels. Titanium was found to be the most robust material, displaying no adverse affect from this exposure, whilst aluminium was found to be substantially less durable. The PEEK carbon fibre composite showed signs of surface degradation after only two months of flight trials. © 2003 Éditions scientifiques et médicales Elsevier SAS. All rights reserved.
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| 5. |
- Berggren, Daniel
(författare)
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Investigation of limit cycle oscillations for a wing section with nonlinear stiffness
- 2004
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Ingår i: Aerospace Science and Technology. - : Elsevier BV. - 1270-9638 .- 1626-3219. ; 8:1, s. 27-34
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Tidskriftsartikel (refereegranskat)abstract
- A wind tunnel experiment is designed with the objective to obtain well-behaved limit cycle oscillations for a wing section with two degrees of freedom, translation and rotation, in two-dimensional flow. This is accomplished using a setup of linear springs so that the resulting moment is a nonlinear function of the rotation angle. The experimental setup is designed so that the amplitudes of the limit cycle oscillations are sufficiently low to motivate the use of linear aerodynamics in the analysis. The experimental results are compared to analyses for two different configurations, and the agreement is fairly good.
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| 6. |
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