Publication: Adjoint-Based Optimization of PDEs in Moving Domains

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Title	Adjoint-Based Optimization of PDEs in Moving Domains
Authors/Editors*	B. Protas and W. Liao
Where published*	Journal of Computational Physics
How published*	Journal
Year*	2008
Volume	(in press)
Number
Pages
Publisher
Keywords
Link	http://dx.doi.org/10.1016/j.jcp.2007.11.014
Abstract	In this investigation we address the problem of adjointâbased optimization of PDE systems in moving domains. As an example we consider the oneâdimensional heat equation with prescribed boundary temperatures and heat fluxes. We discuss two methods of deriving an adjoint system necessary to obtain a gradient of a cost functional. In the first approach we derive the adjoint system after mapping the problem to a fixed domain, whereas in the second approach we derive the adjoint directly in the moving domain by employing methods of the noncylindrical calculus. We show that the operations of transforming the system from a variable to a fixed domain and deriving the adjoint do not commute and that, while the gradient information contained in both systems is the same, the second approach results in an adjoint problem with a simpler structure which is therefore easier to implement numerically. This approach is then used to solve a moving boundary optimization problem for our model system.