Naslov
Blok-spregnuti algoritam za dvo-jednadžbene modele turbulencije
(Block-Coupled Solution Algorithms for 2-equation Turbulence Models)

Autori
Keser, Robert

Vrsta, podvrsta i kategorija rada
Ocjenski radovi, diplomski rad, diplomski

Fakultet
Fakultet strojarstva i brodogradnje

Mjesto
Zagreb

Datum
25.03

Godina
2016

Stranica
110

Mentor
Jasak, Hrvoje

Ključne riječi
CFD ; OpenFOAM ; foam-extend ; turbulence modelling ; k-e k-omega SST ; block-matrix ; implicit coupling ; lineartisation ; validation ; benchmarking

Sažetak
Modern implicitly coupled pressure–velocity algorithms introduced a considerable increase in the convergence rates when compared with segregated algorithms. Although, segregated treatment of turbulence model equations often limits such algorithms from reaching their full potential. Hence, implicit coupling of two- equation turbulence models is investigated. In order to implement the implicitly coupled turbulence models in the block-matrix framework, it is necessary to linearise the non-linear source and sink terms. The linearised sources and sinks also need to undergo the stability and boundedness analysis. Linearisation and implementation of two-equation turbulence models, k-epsilon and k-omega SST, in foam- extend (the community-driven fork f the OpenFOAM) software is presented. Validation of implemented turbulence models is performed. The two validation cases are: a separated flow past a NACA 4412 airfoil at maximum lift and an incompressible turbulent flow over a backward facing step. Validation of the implicitly coupled k-omega SST model is performed for both cases, whereas validation of the implicitly coupled k-epsilon model is performed only for the backward facing step case. Finally, performance of implemented turbulence models is compared with existing segregated models. Benchmarking is performed on the two validation cases. Similarly as for the validation, both implemented turbulence models are benchmarked on the backward facing step case and only the k- omega SST is benchmarked on the NACA 4412 case.

Izvorni jezik
Engleski

Znanstvena područja
Strojarstvo

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