Identification of linear and nonlinear aerodynamic impulse responses using digital filter techniques

Silva, Walter A.

doi:10.2514/6.1997-3712

Cited by 51 publications

(31 citation statements)

References 16 publications

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“…This traditional form of reasoning has led many authors [14,15,16,17] to justify the use of smooth pulse excitations, since the theoretical continuous-time impulse and indicial excitations would not be numerically feasible. However, Silva [18] demonstrates that, once the governing equations have been discretized, the resulting numerical scheme is actually a discrete-time system, which has its own properties and peculiarities. Hence, Ref.…”

Section: Impulsive Responses and Discrete Solutionsmentioning

confidence: 99%

A Non-Parametric Technique for Aerodynamic State Identification for Flutter Prediction

Azevedo¹,

Azevedo²,

Silva³

2014

Proceedings of 10th World Congress on Computational Mechanics

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Section: Impulsive Responses and Discrete Solutionsmentioning

confidence: 99%

A Non-Parametric Technique for Aerodynamic State Identification for Flutter Prediction

Azevedo¹,

Azevedo²,

Silva³

2014

Proceedings of 10th World Congress on Computational Mechanics

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“…Volterra-based ROMs were also considered, but discarded by comparison with POD-based ROMs during the preliminary problem work. Most of this investigation was based on Silva's work, [126][127][128][129][130][131][132][133] with some additional reference regarding application of Volterra kernels and their requisite components. [134][135][136] Although effective when applied appropriately, it was determined that they were not well suited for the goals of this research.…”

Section: Background and Related Workmentioning

confidence: 99%

Reduced-Order Techniques for Sensitivity Analysis and Design Optimization of Aerospace Systems

Parrish

2015

AIAA Journal

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This work proposes a new method for using reduced order models in lieu of high fidelity analysis during the sensitivity analysis step of gradient based design optimization.The method offers a reduction in the computational cost of finite difference based sensitivity analysis in that context. The method relies on interpolating reduced order models which are based on proper orthogonal decomposition. The interpolation process is performed using radial basis functions and Grassmann manifold projection. It does not require additional high fidelity analyses to interpolate a reduced order model for new points in the design space.The interpolated models are used specifically for points in the finite difference stencil during sensitivity analysis.The proposed method is applied to an airfoil shape optimization (ASO) problem and a transport wing optimization (TWO) problem. The errors associated with the reduced order models themselves as well as the gradients calculated from them are evaluated. The effects of the method on the overall optimization path, computation times, and function counts are also examined.

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“…If a linearized version of the non-linear CFD code is not available, an alternative approach to obtain approximate linear responses from a non-linear CFD code is available using Volterra theory [8][9][10] . A truncated Volterra series for small inputs can be used to represent the solution for weakly non-linear systems.…”

Section: Pulse Extractionmentioning

confidence: 99%

Reduced Order Modelling of Aircraft Gust Response for Use in Early Design Stages

Williams

Jones

Gaitonde

et al. 2017

35th AIAA Applied Aerodynamics Conference

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms This paper expands on the work previous carried out by authors in exploring the role Reduced Order Models (ROMs) can play in the early stages of the aircraft design cycle, particularly in respect of modelling the response to atmospheric gusts. Gusts have a large impact on the development of aircraft due to their prevalence among the critical design cases for loads. Despite this, the traditional methods of modelling such cases are restricted due to high costs associated with both wind tunnel testing and Computational Fluid Dynamics (CFD) simulation. This is particularly problematic and restrictive during those early design stages where designs may change significantly and frequently. ROMs have been shown to be capable of reproducing gust responses at lower costs compared to the high fidelity simulations, and previous work presented by the authors introduced a number of techniques that could be used to make the process of gust ROM creation more efficient without loss of accuracy. This paper explores the strengths and weaknesses of these approaches in more detail and introduces further new techniques to improve efficiency. In particular this paper will consider more complex test cases which better reflect the industrial demands upon such a tool which is likely to be used in the design of aircraft.

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Identification of linear and nonlinear aerodynamic impulse responses using digital filter techniques

Cited by 51 publications

References 16 publications

A Non-Parametric Technique for Aerodynamic State Identification for Flutter Prediction

A Non-Parametric Technique for Aerodynamic State Identification for Flutter Prediction

Reduced-Order Techniques for Sensitivity Analysis and Design Optimization of Aerospace Systems

Reduced Order Modelling of Aircraft Gust Response for Use in Early Design Stages

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