MODELING OF FLOWS THROUGH A CHANNEL BY THE NAVIER–STOKES VARIATIONAL INEQUALITIES

Autor: Stanislav Kračmar, Jiří Neustupa
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Acta Polytechnica, Vol 61, Iss SI, Pp 89-98 (2021)
Druh dokumentu: article
ISSN: 1210-2709
1805-2363
DOI: 10.14311/AP.2021.61.0089
Popis: We deal with a mathematical model of a flow of an incompressible Newtonian fluid through a channel with an artificial boundary condition on the outflow. We explain how several artificial boundary conditions formally follow from appropriate variational formulations and the way one expresses the dynamic stress tensor. As the boundary condition of the “do nothing”–type, that is predominantly considered to be the most appropriate from the physical point of view, does not enable one to derive an energy inequality, we explain how this problem can be overcome by using variational inequalities. We derive a priori estimates, which are the core of the proofs, and present theorems on the existence of solutions in the unsteady and steady cases.
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