Aeroelastic simulations using gridless boundary condition and small perturbation techniques

The paper presents a flutter suppression control design for a prototype wing. The present approach includes numerical modeling of aeroservoelastic system, reduced-order modeling, and robust control law design to arrive at an active flutter suppression control. The resulting control is implemented and tested for its effectiveness in wind-tunnel experiments. Computational aeroelastic techniques 11 and nonlinear reduced-order modeling methods 16, 17 are applied to obtain a mathematical representation of the system useful for control law design. Robust control design follows the H ∞ fixed-order output-feedback (HIFOO) controller by means of a non-convex local optimization algorithm that offers the advantage of stability guarantee when a solution is found, and handling of non-smooth gradients encountered in non-convex problems. 5, 6, 15 The developed flutter suppression control design was implemented and tested with a specially designed wind-tunnel wing model. 14 Wind tunnel tests of closed-loop control confirm the validity of the present approach, where more than 90% attenuation of LCO has been recorded.

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“…The AE system forms an inner closedloop. It follows from (11) and (12) that the AE closed-loop equations are: …”

Section: A State-space Model Setupmentioning

confidence: 99%

Flutter Suppression for a Prototype Wing - Numerical Modeling, Control Law Design, and Experimental Results

Lai

Cui

et al. 2016

AIAA Modeling and Simulation Technologies Conference

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“…A method is presented here based on RBFs, which are multivariate function kernels allowing volume data interpolation in n ‐dimensional space. RBFs have been proven extremely effective in several areas of computational methods, for example, fluid‐structure coupling force and displacement transformation and mesh deformation , surface parameterisation and optimisation , and adaptive sampling and metamodeling , and have also found some use in boundary (physical boundaries as opposed to zonal interfaces) problems; both Lai et al and Le have used them to reconstruct solid wall boundary conditions. A brief investigation of RBFs in the context of an overset mesh was also carried out by Li and Chen .…”

Section: Introductionmentioning

confidence: 99%

Numerical study of radial basis function interpolation for data transfer across discontinuous mesh interfaces

Costin

Allen

2013

Numerical Methods in Fluids

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SUMMARYAllowing discontinuous or non‐matching mesh spacing across zonal interfaces within a computational domain offers many advantages, particularly in terms of easing the mesh generation process, reduction of required mesh densities, and relative motion between mesh zones. This paper presents a numerical study of a universal method for interpolating solution data across such interfaces. The method utilises radial basis functions (RBFs) for n‐dimensional volume interpolation, and treats the available solution data points simply as arbitrary clouds of points, eliminating all connectivity requirements and making it applicable to a wide range of computational problems. Properties of the developed meshless interface interpolation are investigated using analytic functions, and three issues are considered: the achievable order of spatial accuracy of the RBF interpolation alone and comparison with a variable order polynomial; the effect of a combined RBF and polynomial interpolation; and the ability of the method to recover frequency content. RBF interpolation alone is shown to achieve fourth‐order to sixth‐order spatial accuracy in one and two dimensions, and in three dimensions, using a small number of data points, third‐order and above is achievable even for a 3 : 1 discontinuous cell spacing ratio, that is a 27 : 1 volume ratio, across the interface. Hence, it is inefficient to include polynomial terms, since improving on the RBF spatial accuracy results in a significant increase in the system size and deterioration in conditioning. It is also shown that only five points per wavelength are required to capture both frequency and amplitude content of periodic solutions to less than 0.01% error.Copyright © 2013 John Wiley & Sons, Ltd.

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“…Cloud points are selected based on their proximity to the reflected node and their location on the outward normal direction of the surface. A number of 12 cloud points are used in the present RBF implementation so as to achieve an accuracy that is comparable to that of a second order least-squares based interpolation method (See Carolina et al 3 an d Lai et al 18 ). The slip boundary condition on the boundary surface is applied.…”

Section: A Unsteady Flows Analysismentioning

confidence: 98%

“…. Solution to Eq (18). can be obtained by a number of methods, for example the Duhamel's Integral solution.…”

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confidence: 99%

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Simulation of Transonic Aeroservoelasticity Using Cartesian-Grid Based Flow Solver

Zhang

Lai

2012

42nd AIAA Fluid Dynamics Conference and Exhibit

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The paper presents a numerical method for solving the aeroservoelastic problems. The method uses computational fluid dynamics and computational structural dynamics in a tightly-coupled manner to obtain time-accurate solutions of the generalized aeroelastic equations of motion. The transpiration method is applied to model the kinematic boundary conditions of moving surfaces in a Cartesian-grid based flow solver. The result is an efficient method for solving aeroelastic and aeroservoelastic problems even for very complex configurations. In this paper, numerical results for the verification of the developed method are presented. As a prelude to flutter-suppression control design using trailingedge flap, the effects of flap deflection on aeroelastic response of an experimental wing are studied. Preliminary results are presented in the paper.

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Aeroelastic simulations using gridless boundary condition and small perturbation techniques

Cited by 14 publications

References 39 publications

Flutter Suppression for a Prototype Wing - Numerical Modeling, Control Law Design, and Experimental Results

Flutter Suppression for a Prototype Wing - Numerical Modeling, Control Law Design, and Experimental Results

Numerical study of radial basis function interpolation for data transfer across discontinuous mesh interfaces

Simulation of Transonic Aeroservoelasticity Using Cartesian-Grid Based Flow Solver

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