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Amoignon, Olivier
Publications (7 of 7) Show all publications
Jakobsson, S. & Amoignon, O. (2007). Mesh deformation using radial basis functions for gradient-based aerodynamic shape optimization. Computers & Fluids, 36, 1119-1136
Open this publication in new window or tab >>Mesh deformation using radial basis functions for gradient-based aerodynamic shape optimization
2007 (English)In: Computers & Fluids, ISSN 0045-7930, E-ISSN 1879-0747, Vol. 36, p. 1119-1136Article in journal (Refereed) Published
National Category
Computational Mathematics Computer Sciences
Identifiers
urn:nbn:se:uu:diva-22158 (URN)10.1016/j.compfluid.2006.11.002 (DOI)000246537700008 ()
Projects
Design Optimization
Available from: 2007-04-16 Created: 2007-04-16 Last updated: 2018-01-12Bibliographically approved
Amoignon, O. & Berggren, M. (2006). Adjoint of a median-dual finite-volume scheme: Application to transonic aerodynamic shape optimization.
Open this publication in new window or tab >>Adjoint of a median-dual finite-volume scheme: Application to transonic aerodynamic shape optimization
2006 (English)Report (Other academic)
Series
Technical report / Department of Information Technology, Uppsala University, ISSN 1404-3203 ; 2006-013
National Category
Computational Mathematics Computer Sciences
Identifiers
urn:nbn:se:uu:diva-80174 (URN)
Projects
Design Optimization
Available from: 2007-09-16 Created: 2007-09-16 Last updated: 2018-01-13Bibliographically approved
Amoignon, O. (2006). Moving mesh adaptation scheme for aerodynamic shape optimization.
Open this publication in new window or tab >>Moving mesh adaptation scheme for aerodynamic shape optimization
2006 (English)Report (Other academic)
Series
Technical report / Department of Information Technology, Uppsala University, ISSN 1404-3203 ; 2006-014
National Category
Computational Mathematics Computer Sciences
Identifiers
urn:nbn:se:uu:diva-80175 (URN)
Projects
Design Optimization
Available from: 2007-09-17 Created: 2007-09-17 Last updated: 2018-01-13Bibliographically approved
Amoignon, O., Pralits, J., Hanifi, A., Berggren, M. & Henningson, D. (2006). Shape optimization for delay of laminar-turbulent transition. AIAA Journal, 44, 1009-1024
Open this publication in new window or tab >>Shape optimization for delay of laminar-turbulent transition
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2006 (English)In: AIAA Journal, ISSN 0001-1452, E-ISSN 1533-385X, Vol. 44, p. 1009-1024Article in journal (Refereed) Published
National Category
Computational Mathematics Computer Sciences
Identifiers
urn:nbn:se:uu:diva-80640 (URN)10.2514/1.12431 (DOI)000237492000010 ()
Projects
Design Optimization
Available from: 2007-01-31 Created: 2007-01-31 Last updated: 2018-01-13Bibliographically approved
Amoignon, O. (2005). Numerical Methods for Aerodynamic Shape Optimization. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Numerical Methods for Aerodynamic Shape Optimization
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Gradient-based aerodynamic shape optimization, based on Computational Fluid Dynamics analysis of the flow, is a method that can automatically improve designs of aircraft components. The prospect is to reduce a cost function that reflects aerodynamic performances.

When the shape is described by a large number of parameters, the calculation of one gradient of the cost function is only feasible by recourse to techniques that are derived from the theory of optimal control. In order to obtain the best computational efficiency, the so called adjoint method is applied here on the complete mapping, from the parameters of design to the values of the cost function. The mapping considered here includes the Euler equations for compressible flow discretized on unstructured meshes by a median-dual finite-volume scheme, the primal-to-dual mesh transformation, the mesh deformation, and the parameterization. The results of the present research concern the detailed derivations of expressions, equations, and algorithms that are necessary to calculate the gradient of the cost function. The discrete adjoint of the Euler equations and the exact dual-to-primal transformation of the gradient have been implemented for 2D and 3D applications in the code Edge, a program of Computational Fluid Dynamics used by Swedish industries.

Moreover, techniques are proposed here in the aim to further reduce the computational cost of aerodynamic shape optimization. For instance, an interpolation scheme is derived based on Radial Basis Functions that can execute the deformation of unstructured meshes faster than methods based on an elliptic equation.

In order to improve the accuracy of the shape, obtained by numerical optimization, a moving mesh adaptation scheme is realized based on a variable diffusivity equation of Winslow type. This adaptation has been successfully applied on a simple case of shape optimization involving a supersonic flow. An interpolation technique has been derived based on a mollifier in order to improve the convergence of the coupled mesh-flow equations entering the adaptive scheme.

The method of adjoint derived here has also been applied successfully when coupling the Euler equations with the boundary-layer and parabolized stability equations, with the aim to delay the laminar-to-turbulent transition of the flow. The delay of transition is an efficient way to reduce the drag due to viscosity at high Reynolds numbers.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2005. p. 34
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 135
Keywords
Computational Fluid Dynamics, shape optimization, adjoint equations, edge-based finite-volume method, moving mesh adaptation, radial basis functions, inviscid compressible flow, transition control
National Category
Computational Mathematics
Research subject
Numerical Analysis
Identifiers
urn:nbn:se:uu:diva-6252 (URN)91-554-6431-9 (ISBN)
Public defence
2006-01-20, Room 2446, Polacksbacken, Lägerhyddsvägen 2D, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2005-12-28 Created: 2005-12-28 Last updated: 2014-09-03Bibliographically approved
Amoignon, O. (2003). Adjoint-based aerodynamic shape optimization. (Licentiate dissertation). Uppsala University
Open this publication in new window or tab >>Adjoint-based aerodynamic shape optimization
2003 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

An adjoint system of the Euler equations of gas dynamics is derived in order to solve aerodynamic shape optimization problems with gradient-based methods. The derivation is based on the fully discrete flow model and involves differentiation and transposition of the system of equations obtained by an unstructured and node-centered finite-volume discretization. Solving the adjoint equations allows an efficient calculation of gradients, also when the subject of optimization is described by hundreds or thousands of design parameters.

Such a fine geometry description may cause wavy or otherwise irregular designs during the optimization process. Using the one-to-one mapping defined by a Poisson problem is a known technique that produces smooth design updates while keeping a fine resolution of the geometry. This technique is extended here to combine the smoothing effect with constraints on the geometry, by defining the design updates as solutions of a quadratic programming problem associated with the Poisson problem.

These methods are applied to airfoil shape optimization for reduction of the wave drag, that is, the drag caused by gas dynamic effects that occur close to the speed of sound. A second application concerns airfoil design optimization to delay the laminar-to-turbulent transition point in the boundary layer in order to reduce the drag. The latter application has been performed by the author with collaborators, also using gradient-based optimization. Here, the growth of convectively unstable disturbances are modeled by successively solving the Euler equations, the boundary layer equations, and the parabolized stability equations.

Place, publisher, year, edition, pages
Uppsala University, 2003
Series
Information technology licentiate theses: Licentiate theses from the Department of Information Technology, ISSN 1404-5117 ; 2003-012
National Category
Computational Mathematics
Research subject
Numerical Analysis
Identifiers
urn:nbn:se:uu:diva-86142 (URN)
Supervisors
Available from: 2003-10-16 Created: 2007-01-24 Last updated: 2017-08-31Bibliographically approved
Amoignon, O. & Berggren, M. (2003). Discrete adjoint-based shape optimization for an edge-based finite-volume solver. In: Computational Fluid and Solid Mechanics: 2003 (pp. 2190-2193). Elsevier Science
Open this publication in new window or tab >>Discrete adjoint-based shape optimization for an edge-based finite-volume solver
2003 (English)In: Computational Fluid and Solid Mechanics: 2003, Elsevier Science , 2003, p. 2190-2193Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Elsevier Science, 2003
National Category
Computational Mathematics Computer Sciences
Identifiers
urn:nbn:se:uu:diva-48499 (URN)10.1016/B978-008044046-0.50537-6 (DOI)0-08-044046-0 (ISBN)
Projects
Design Optimization
Available from: 2007-01-31 Created: 2007-01-31 Last updated: 2018-01-11Bibliographically approved
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