The Effects of External Stores on Nonlinear Aeroelastic Responses

Kim, Kiun; Strganac, Thomas W.

doi:10.2514/6.2004-1942

Cited by 5 publications

(3 citation statements)

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“…To focus on the interaction between the bending (out-of-plane) motion and torsion behaviour, it is assumed that the aeroelastic Table 1 Baseline system parameters Fig. 1 The geometry and nomenclature of a generic cantilever wing-with-store configuration [27,28,37] responses are dominated by the first bending and torsion modes and all the modes that are not directly excited by external loads or indirectly excited by any resonance mechanism decay with time [27]. Therefore, only one mode in each motion is used to describe the response.…”

Section: Resultsmentioning

confidence: 99%

“…Substituting the variational expressions into the extended form of Hamilton's principle, using the relationship between the Euler angles and the displacement, applying Taylor-series expansion and the ordering scheme, and discarding the terms higher than third order, the non-linear bending -bendingtorsion aeroelastic governing equations can be obtained. More detail of the derivation of the equations of motion can be found in references [27] and [37]. The equations account for both in-plane and out-of-plane motion, yet if the in-plane rigidity is relatively high, then the in-plane response will be of minimal influence on the out-of-plane motion.…”

Section: Non-linear Structural and Aerodynamic Modellingmentioning

confidence: 99%

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Non-linear aeroelastic investigations of store(s)-induced limit cycle oscillations

Abbas

Chen

Marzocca

et al. 2008

Proceedings of the Institution of Mechanical Engineers, Part G:

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In the current work, the study of the aeroelastic behaviour of a wing with external store(s), such as a missile or drop fuel tank, is presented. The aeroelastic governing equations derived for a cantilever wing with coupled bending and torsion modes account for structural and aerodynamic non-linearities. Coupling terms retained in the aeroelastic governing equations are due to: (a) the non-linear beam theory, (b) the aerodynamic non-linearities of a quasi-steady model with stall, and (c) the non-linear kinematics terms of the store(s). As presented in the paper, this aircraft configuration can induce pathologies, such as store(s)-induced limit cycle oscillations (or si-LCOs), very different from the one of a clean wing configuration, and from the one obtained from the linearized form of the aeroelastic governing equations. Time domain simulation, phase portrait, and bifurcation analyses are performed for various velocities, initial conditions, and store(s)-sensitive parameters — such as store mass, number, location along the wing — to examine the dynamic aeroelastic instabilities of the system (e.g. the onset of flutter and LCO). Numerical studies indicate the presence of regions of subcritical Hopf-bifurcation, corresponding to an unstable LCO, for velocities below the linear flutter velocity.

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Section: Resultsmentioning

confidence: 99%

Section: Non-linear Structural and Aerodynamic Modellingmentioning

confidence: 99%

Non-linear aeroelastic investigations of store(s)-induced limit cycle oscillations

Abbas

Chen

Marzocca

et al. 2008

Proceedings of the Institution of Mechanical Engineers, Part G:

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“…In work by Kim and Strganac [13], the LCO of a cantilevered wing with stores was modeled using a nonlinear beam model that included both kinematic and geometric nonlinearities. The aerodynamic model used was a nonlinear quasi-steady model with a subsonic stall model.…”

Section: Introductionmentioning

confidence: 99%

Delta Wing with Store Limit-Cycle-Oscillation Modeling Using a High-Fidelity Structural Model

Attar

Dowell

Tang

2008

Journal of Aircraft

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The flutter and limit-cycle oscillation behavior of a 45-deg delta-wing-store model with various store spanwise locations is studied using an aeroelastic model that includes a high-fidelity nonlinear finite element structural solver and a vortex-lattice aerodynamic model. The store aerodynamics are modeled using slender-body theory. The computed results are compared with a previous computational model and with the experiment. The zero-angle-ofattack flutter behavior of the wing-store configuration is shown to be sensitive to the spanwise store location. This is predicted accurately using the current methodology. Limit-cycle oscillation results for zero angle of attack are computed for two store spanwise locations and compare favorably with the experiment. For a clean-wing configuration and a configuration that had the store located at y=c 0:291, the flutter results show very little sensitivity to the model angle of attack. This too was predicted accurately using the current model. However, when the store is placed at y=c 0:545, the experimental flutter data show a large sensitivity to angle of attack, with the flutter velocity decreasing by almost 20% when the model is placed at an angle of attack of 2 deg. This is not predicted in the current work and it is possible that unmodeled flow physics such as leading-edge vortices are the cause of this difference.

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