Efficient Monolithic Solution Algorithm for High-Fidelity Aerostructural Analysis and Optimization

Zhang, Jenmy Zimi; Zingg, David W.

doi:10.2514/1.j056163

Cited by 14 publications

(5 citation statements)

References 48 publications

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“…The orthogonality of the residual r (1) k to the subspace AK k (A, r (1) 0 ) spanned by the columns of C k is known as the optimality property of the residual. In practice, GCR is not considered as a means to solve the linear system.…”

Section: A Flexible Generalized Conjugate Residual With Inner Orthogo...mentioning

confidence: 99%

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Recycling Krylov Subspaces for Efficient Partitioned Solution of Aerostructural Coupled Adjoint Systems

Jadoui

Blondeau

Roux

2022

AIAA AVIATION 2022 Forum

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Robust and efficient solvers for coupled-adjoint linear systems are crucial to successful aerostructural optimization. Monolithic and partitioned strategies can be applied. The monolithic approach is expected to offer better robustness and efficiency for strong fluid-structure interactions. However, it requires a high implementation cost and convergence may depend on appropriate scaling and initialization strategies. On the other hand, the modularity of the partitioned method enables a straightforward implementation while its convergence may require relaxation. In addition, a partitioned solver leads to a higher number of iterations to get the same level of convergence as the monolithic one. The objective of this paper is to accelerate the partitioned solver by considering techniques borrowed from Krylov subspace recycling strategies adapted to sequences of linear systems with varying right-hand sides. Indeed, in a partitioned framework, the structural source term attached to the fluid block of equations affects the right-hand side with the nice property of quickly converging to a constant value. We will also consider error approximation and approximate eigenvectors deflation in conjunction with advanced inner-outer Krylov solvers for the fluid block equations. We demonstrate the benefit of these techniques by computing the coupled derivatives for an aeroelastic configuration of the ONERA-M6 fixed wing in transonic flow. For this exercise the fluid grid was coupled to a structural model specifically designed to exhibit a high flexibility. All computations are performed using RANS flow modeling and a fully linearized one-equation Spalart-Allmaras turbulence model.

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Section: A Flexible Generalized Conjugate Residual With Inner Orthogo...mentioning

confidence: 99%

“…In a high-fidelity aerostructural optimization context, Zhang and Zingg [1] implemented a robust monolithic solution method for both aerostructural analysis and coupled adjoint problem. A three-dimensional formulation was adopted involving the mesh, the flow and the structural states.…”

mentioning

confidence: 99%

Recycling Krylov Subspaces for Efficient Partitioned Solution of Aerostructural Coupled Adjoint Systems

Jadoui

Blondeau

Roux

2022

AIAA AVIATION 2022 Forum

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“…A large part of published MDO studies in the context of aircraft design focuses on aerostructural optimization problems with a particular interest in employing high-fidelity methods like RANS and FEM [1][2][3][4]. Extending the MDO design space by engine design variables is a promising idea, since the engine sizing has a large influence on both the structural sizing process, e.g.…”

Section: State Of the Artmentioning

confidence: 99%

Hybrid Surrogate-Based Rubber Engine Model for Aircraft Multidisciplinary Design Optimization

Häßy

Schmeink

Becker

et al. 2020

Aiaa Aviation 2020 Forum

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“…Discipline-specific preconditioners from the fluid and structural solvers were reused in Kenway, Kennedy & Martins (2014) in a block-Jacobi fashion, noting that discarding the off-diagonal coupling terms allows for easier parallelisation. Block-Jacobi and Gauss-Seidel preconditioners for a three-field formulation were compared in Zhang & Zingg (2018). While this is an intricate discussion, clear performance gains were realised overall when including various coupling terms.…”

Section: Introductionmentioning

confidence: 99%

Global stability analysis of elastic aircraft in edge-of-the-envelope flow

Houtman

Timme

2023

J. Fluid Mech.

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Shock buffet on wings is a phenomenon caused by strong shock-wave/boundary-layer interaction resulting first in self-sustained flow unsteadiness and eventually in a detrimental structural response called buffeting. While it is an important aspect of wing design and aircraft certification, particularly for modern transonic air transport, not all of the underlying multidisciplinary physics is thoroughly understood. Building upon a single-discipline shock-buffet stability study, this work now investigates the impact of an elastic structure in these extreme flow conditions. Specifically, a triglobal stability analysis of a fluid–structure coupled system is presented, utilising the implicitly restarted Arnoldi method with a sparse iterative Krylov solver and novel preconditioner. Asymmetry resulting from a static aeroelastic simulation based on a finite-element model of the underlying geometry in a wind tunnel modifies the global modes of the earlier fluid-only symmetric full-span analysis. A flutter stability analysis at wind-tunnel flow conditions below shock-buffet onset finds no instability in the structural degrees-of-freedom, whereas in shock-buffet flow with globally unstable fluid modes additional marginally unstable structural (and fluid) modes emerge. The developed stability tool for coupled analysis is instrumental in identifying those physically relevant and strongly coupled modes where a standard pk-type (p being eigenvalue and k reduced frequency) flutter analysis fails. With the complementary computation of adjoint eigenmodes, the core of the instability is pinpointed to a relatively small wing area which may help to effect the control and delay of this detrimental transonic unsteadiness. We contribute to the question on how the presence of the elastic wing structure impacts on the otherwise pure aerodynamic three-dimensional shock-buffet dynamics.

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Efficient Monolithic Solution Algorithm for High-Fidelity Aerostructural Analysis and Optimization

Cited by 14 publications

References 48 publications

Recycling Krylov Subspaces for Efficient Partitioned Solution of Aerostructural Coupled Adjoint Systems

Recycling Krylov Subspaces for Efficient Partitioned Solution of Aerostructural Coupled Adjoint Systems

Hybrid Surrogate-Based Rubber Engine Model for Aircraft Multidisciplinary Design Optimization

Global stability analysis of elastic aircraft in edge-of-the-envelope flow

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