eprintid: 9691 rev_number: 9 eprint_status: archive userid: 1 dir: disk0/00/00/96/91 datestamp: 2009-07-30 15:29:10 lastmod: 2015-04-24 23:21:52 status_changed: 2012-08-14 15:30:22 type: preprint metadata_visibility: show creators_name: Lebiedz, Dirk creators_name: Reinhardt, Volkmar creators_name: Siehr, Jochen title: Minimal Curvature Trajectories: Riemannian Geometry Concepts for Model Reduction in Chemical Kinetics ispublished: pub subjects: 510 divisions: 708000 keywords: langsame invariante Mannigfaltigkeitmodel reduction , slow invariant manifold , chemical kinetics , nonlinear optimization , Riemannian geometry cterms_swd: Ordnungsreduktion cterms_swd: Reaktionskinetik cterms_swd: Nichtlineare Optimierung cterms_swd: Riemannsche Geometrie cterms_swd: Krümmung abstract: In dissipative ordinary differential equation systems different time scales cause anisotropic phase volume contraction along solution trajectories. Model reduction methods exploit this for simplifying chemical kinetics via a time scale separation into fast and slow modes. The aim is to approximate the system dynamics with a dimension-reduced model after eliminating the fast modes by enslaving them to the slow ones via computation of a slow attracting manifold. We present a novel method for computing approximations of such manifolds using trajectory-based optimization. We discuss Riemannian geometry concepts as a basis for suitable optimization criteria characterizing trajectories near slow attracting manifolds and thus provide insight into fundamental geometric properties of multiple time scale chemical kinetics. The optimization criteria correspond to a suitable mathematical formulation of "minimal relaxation" of chemical forces along reaction trajectories under given constraints. We present various geometrically motivated criteria and the results of their application to three test case reaction mechanisms serving as examples. We demonstrate that accurate numerical approximations of slow invariant manifolds can be obtained. abstract_translated_lang: eng class_scheme: pacs class_labels: 37M99, 37N40, 92E20, 80A30 date: 2009 date_type: published id_scheme: DOI id_number: 10.11588/heidok.00009691 ppn_swb: 164821147X own_urn: urn:nbn:de:bsz:16-opus-96911 language: eng bibsort: LEBIEDZDIRMINIMALCUR2009 full_text_status: public citation: Lebiedz, Dirk ; Reinhardt, Volkmar ; Siehr, Jochen (2009) Minimal Curvature Trajectories: Riemannian Geometry Concepts for Model Reduction in Chemical Kinetics. [Preprint] document_url: https://archiv.ub.uni-heidelberg.de/volltextserver/9691/1/Lebiedz2009.pdf