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Optimization and Computational Fluid Dynamics - Department of ...

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Chapter 3<br />

Mathematical Aspects <strong>of</strong> CFD-based<br />

<strong>Optimization</strong><br />

Hans Georg Bock <strong>and</strong> Volker Schulz<br />

Abstract There exist several computational strategies <strong>of</strong> different efficiency<br />

for the solution <strong>of</strong> model-based optimization problems – particularly, in the<br />

case <strong>of</strong> models based on challenging CFD problems. Applied mathematics<br />

provides means for their analysis <strong>and</strong> for advice on their proper usage.<br />

In this chapter, methods are mainly analyzed based on the explicit treatment<br />

<strong>of</strong> the underlying CFD-problem as a constraint <strong>of</strong> a nonlinear optimization<br />

problem, thus providing the potential for high computational efficiency.<br />

Methods <strong>of</strong> this form are termed optimization boundary value problem methods,<br />

simultaneous optimization methods or one-shot optimization methods.<br />

The necessary conditions <strong>of</strong> optimality play a key structural role in devising<br />

those strategies. Special attention is given to the following issues: modular<br />

sequential quadratic programming with approximate linear solvers, preconditioning<br />

<strong>of</strong> the Karush-Kuhn-Tucker (KKT) system <strong>and</strong> multigrid optimization<br />

in the case <strong>of</strong> stationary problems. In the case <strong>of</strong> unsteady problems, we<br />

will concentrate on time-domain decomposition such as by multiple shooting,<br />

<strong>and</strong> on algorithmic developments for real-time optimization. The aim <strong>of</strong><br />

the presentation is to give a survey on advanced <strong>and</strong> fast methods for optimization<br />

within a CFD framework. For details, the reader is referred to the<br />

relevant literature.<br />

Hans Georg Bock<br />

Interdisciplinary Center for Scientific Computing (IWR),<br />

University <strong>of</strong> Heidelberg, Germany<br />

(e-mail: Bock@iwr.uni-heidelberg.de)<br />

Volker Schulz<br />

<strong>Department</strong> <strong>of</strong> Mathematics, University <strong>of</strong> Trier, Germany<br />

(e-mail: Volker.Schulz@uni-trier.de)<br />

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