A newton-krylov solver with a loosely-coupled turbulence model for aerodynamic flows


Blanco, Max (2006) A newton-krylov solver with a loosely-coupled turbulence model for aerodynamic flows University of Toronto, Department of Aerospace Sciences, Doctoral Thesis , 160pp.

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Description/Abstract

ex Computational solutions of the Navier-Stokes equations have proven to be a useful tool in the design of aircraft. A Newton-Krylov flow solver for unstructured grids is developed in order to demonstrate that a formulation in which the mean-flow and turbulence mechanism equations are loosely coupled can be more economical than a similar fully-coupled formulation.
The Favre-averaged Navier-Stokes equations are derived for steady two-dimensional flows, and the turbulence mechanism is described. These equations constitute a model of the physics of aerodynamic flows. The model is validated against experimental data. The objective of this thesis is to examine a means to improve the iterative process by which the solutions are generated. The Newton-Krylov iteration is selected in order to refine the solution, and its features examined. The authors of current Newton-Krylov techniques have fully coupled the turbulence mechanism to the Navier-Stokes equations. A contrast and comparison study made here between the fully-coupled formulation and a loosely-coupled alternative favours the latter. An `equivalent function evaluation' metric is selected for comparison purposes, and is assessed by means of diverse computers. Published results which use the metric are located, and the present loosely-coupled formulation for unstructured grids is found to be significantly faster in this metric than similar fully-coupled formulations. The advantages of the loosely-coupled formulation with respect to the fully-coupled formulation are stated and future avenues for exploitation of the proposed technology are examined. Appendices consist of: a formalism for the Favre average and consequences of its derivation; a short tract on Taylor series; and an essay on the Fr\'echet differential.

Item Type: Thesis (Doctoral)
Subjects:

Organisations: Aerodynamics & Flight Mechanics, Fluid Structure Interactions Group
ePrint ID: 54637
Date :
Date Event
December 2006Published
Date Deposited: 04 Aug 2008
Last Modified: 16 Apr 2017 17:46
Further Information:Google Scholar
URI: http://eprints.soton.ac.uk/id/eprint/54637

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