Abstract:We present numerical computations of the temperature fields in axisymmetric growth apparatus for sublimation growth of silicon carbide (SiC) bulk single crystals by physical vapor transport (PVT) (modified Lely method). The results are computed using our software WIAS-HiTNIHS, the WIAS High Temperature Numerical Induction Heating Simulator; pronunciation: $hit-nice, by solving the energy balance in the entire growth apparatus, taking into account the heat conduction in the solid parts as well as in gas cavitie… Show more
“…4]. More precisely, the software WIAS-HiTNIHS 1 , originally designed for the solution of more general PDE occurring when modeling conductive-radiative heat transfer and electromagnetic heating [2], has been adapted for use in the present context. WIAS-HiTNIHS is based on the program package pdelib [1], it employs the grid generator Triangle [11] to produce constrained Delaunay triangulations of the domains, and it uses the sparse matrix solver GSPAR [3] to solve the linear system arising from the finite volume scheme.…”
International audienceWe consider shape optimization problems with elliptic partial differential state equations.Using regularization and penalization, unknown shapes are encoded via shape functions, turning the shape optimization into optimal control problems for the unknown functions. The method is designed to allow topological changes in a natural way. Based on convergence and differentiability results, numerical algorithms are formulated, using different descent directions and projections. The algorithms are assessed in a series of numerical experiments, applied to an elliptic PDE arising from an oil industry application with two unknown shapes, one giving the region where the PDE is solved, and the other determining the PDE’s coefficients
“…4]. More precisely, the software WIAS-HiTNIHS 1 , originally designed for the solution of more general PDE occurring when modeling conductive-radiative heat transfer and electromagnetic heating [2], has been adapted for use in the present context. WIAS-HiTNIHS is based on the program package pdelib [1], it employs the grid generator Triangle [11] to produce constrained Delaunay triangulations of the domains, and it uses the sparse matrix solver GSPAR [3] to solve the linear system arising from the finite volume scheme.…”
International audienceWe consider shape optimization problems with elliptic partial differential state equations.Using regularization and penalization, unknown shapes are encoded via shape functions, turning the shape optimization into optimal control problems for the unknown functions. The method is designed to allow topological changes in a natural way. Based on convergence and differentiability results, numerical algorithms are formulated, using different descent directions and projections. The algorithms are assessed in a series of numerical experiments, applied to an elliptic PDE arising from an oil industry application with two unknown shapes, one giving the region where the PDE is solved, and the other determining the PDE’s coefficients
“…Step For all the numerical examples discussed subsequently, we stopped the iteration and returned (g fin , p fin ) : [9,12], has been adapted for use in the present context.…”
We consider shape optimization problems, where the state is governed by elliptic partial differential equations (PDE). Using a regularization technique, unknown shapes are encoded via shape functions, turning the shape optimization into optimal control problems for the unknown functions. The method is studied for elliptic PDE to be solved in an unknown region (to be optimized), where the regularization technique together with a penalty method extends the PDE to a larger fixed domain. Additionally, the method is studied for the optimal layout problem, where the unknown regions determine the coefficients of the state equation. In both cases and in arbitrary dimension, the existence of optimal shapes is established for the regularized and the original problem, with convergence of optimal shapes if the regularization parameter tends to zero. Error estimates are proved for the layout problem. In the context of finite element approximations, convergence and differentiability properties are shown. A series of numerical experiments demonstrate the method computationally for an industrially relevant elliptic PDE with two unknown shapes, one giving the region where the PDE is solved, and the other determining the PDE's coefficients.
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