uu.seUppsala universitets publikationer
Ändra sökning
Länk till posten
Permanent länk

Direktlänk
BETA
Amoignon, Olivier
Publikationer (7 of 7) Visa alla publikationer
Jakobsson, S. & Amoignon, O. (2007). Mesh deformation using radial basis functions for gradient-based aerodynamic shape optimization. Computers & Fluids, 36, 1119-1136
Öppna denna publikation i ny flik eller fönster >>Mesh deformation using radial basis functions for gradient-based aerodynamic shape optimization
2007 (Engelska)Ingår i: Computers & Fluids, ISSN 0045-7930, E-ISSN 1879-0747, Vol. 36, s. 1119-1136Artikel i tidskrift (Refereegranskat) Published
Nationell ämneskategori
Beräkningsmatematik Datavetenskap (datalogi)
Identifikatorer
urn:nbn:se:uu:diva-22158 (URN)10.1016/j.compfluid.2006.11.002 (DOI)000246537700008 ()
Projekt
Design Optimization
Tillgänglig från: 2007-04-16 Skapad: 2007-04-16 Senast uppdaterad: 2018-01-12Bibliografiskt granskad
Amoignon, O. & Berggren, M. (2006). Adjoint of a median-dual finite-volume scheme: Application to transonic aerodynamic shape optimization.
Öppna denna publikation i ny flik eller fönster >>Adjoint of a median-dual finite-volume scheme: Application to transonic aerodynamic shape optimization
2006 (Engelska)Rapport (Övrigt vetenskapligt)
Serie
Technical report / Department of Information Technology, Uppsala University, ISSN 1404-3203 ; 2006-013
Nationell ämneskategori
Beräkningsmatematik Datavetenskap (datalogi)
Identifikatorer
urn:nbn:se:uu:diva-80174 (URN)
Projekt
Design Optimization
Tillgänglig från: 2007-09-16 Skapad: 2007-09-16 Senast uppdaterad: 2018-01-13Bibliografiskt granskad
Amoignon, O. (2006). Moving mesh adaptation scheme for aerodynamic shape optimization.
Öppna denna publikation i ny flik eller fönster >>Moving mesh adaptation scheme for aerodynamic shape optimization
2006 (Engelska)Rapport (Övrigt vetenskapligt)
Serie
Technical report / Department of Information Technology, Uppsala University, ISSN 1404-3203 ; 2006-014
Nationell ämneskategori
Beräkningsmatematik Datavetenskap (datalogi)
Identifikatorer
urn:nbn:se:uu:diva-80175 (URN)
Projekt
Design Optimization
Tillgänglig från: 2007-09-17 Skapad: 2007-09-17 Senast uppdaterad: 2018-01-13Bibliografiskt granskad
Amoignon, O., Pralits, J., Hanifi, A., Berggren, M. & Henningson, D. (2006). Shape optimization for delay of laminar-turbulent transition. AIAA Journal, 44, 1009-1024
Öppna denna publikation i ny flik eller fönster >>Shape optimization for delay of laminar-turbulent transition
Visa övriga...
2006 (Engelska)Ingår i: AIAA Journal, ISSN 0001-1452, E-ISSN 1533-385X, Vol. 44, s. 1009-1024Artikel i tidskrift (Refereegranskat) Published
Nationell ämneskategori
Beräkningsmatematik Datavetenskap (datalogi)
Identifikatorer
urn:nbn:se:uu:diva-80640 (URN)10.2514/1.12431 (DOI)000237492000010 ()
Projekt
Design Optimization
Tillgänglig från: 2007-01-31 Skapad: 2007-01-31 Senast uppdaterad: 2018-01-13Bibliografiskt granskad
Amoignon, O. (2005). Numerical Methods for Aerodynamic Shape Optimization. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Öppna denna publikation i ny flik eller fönster >>Numerical Methods for Aerodynamic Shape Optimization
2005 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
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.

Ort, förlag, år, upplaga, sidor
Uppsala: Acta Universitatis Upsaliensis, 2005. s. 34
Serie
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 135
Nyckelord
Computational Fluid Dynamics, shape optimization, adjoint equations, edge-based finite-volume method, moving mesh adaptation, radial basis functions, inviscid compressible flow, transition control
Nationell ämneskategori
Beräkningsmatematik
Forskningsämne
Numerisk analys
Identifikatorer
urn:nbn:se:uu:diva-6252 (URN)91-554-6431-9 (ISBN)
Disputation
2006-01-20, Room 2446, Polacksbacken, Lägerhyddsvägen 2D, Uppsala, 10:15 (Engelska)
Opponent
Handledare
Tillgänglig från: 2005-12-28 Skapad: 2005-12-28 Senast uppdaterad: 2014-09-03Bibliografiskt granskad
Amoignon, O. (2003). Adjoint-based aerodynamic shape optimization. (Licentiate dissertation). Uppsala University
Öppna denna publikation i ny flik eller fönster >>Adjoint-based aerodynamic shape optimization
2003 (Engelska)Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
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.

Ort, förlag, år, upplaga, sidor
Uppsala University, 2003
Serie
IT licentiate theses / Uppsala University, Department of Information Technology, ISSN 1404-5117 ; 2003-012
Nationell ämneskategori
Beräkningsmatematik
Forskningsämne
Numerisk analys
Identifikatorer
urn:nbn:se:uu:diva-86142 (URN)
Handledare
Tillgänglig från: 2003-10-16 Skapad: 2007-01-24 Senast uppdaterad: 2017-08-31Bibliografiskt granskad
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
Öppna denna publikation i ny flik eller fönster >>Discrete adjoint-based shape optimization for an edge-based finite-volume solver
2003 (Engelska)Ingår i: Computational Fluid and Solid Mechanics: 2003, Elsevier Science , 2003, s. 2190-2193Konferensbidrag, Publicerat paper (Refereegranskat)
Ort, förlag, år, upplaga, sidor
Elsevier Science, 2003
Nationell ämneskategori
Beräkningsmatematik Datavetenskap (datalogi)
Identifikatorer
urn:nbn:se:uu:diva-48499 (URN)10.1016/B978-008044046-0.50537-6 (DOI)0-08-044046-0 (ISBN)
Projekt
Design Optimization
Tillgänglig från: 2007-01-31 Skapad: 2007-01-31 Senast uppdaterad: 2018-01-11Bibliografiskt granskad
Organisationer

Sök vidare i DiVA

Visa alla publikationer