Parallel and unstructured computation of 2-D and 3-D vortex flows

Abstract

Vortex flows are main flows which lead to turbulence phenomenon. Turbulence isa complicated and many-faceted problem of fluid dynamics. These flows have striking and varied spatial organizations. Nearly every flow that can be observed in naturehas turbulent character. Consequently, engineering systems in various applicationsare affected by turbulence. Significant examples of such cases are severe efficiencydecreases of pumps and turbines which are designed for a specific design load. There are many cases in combustion or mixing applications where the high mixing and heattransferrates of the turbulent boundary layer are desirable. So, better understandingof turbulent flow regimes requires further investigation of vortex flows. Consistent withthis purpose, several groups of study were performed to cover different types of vortex flows within the context of this study.Firstly, a basic vortex flow is analyzed with various numerical techniques in thisstudy. This test problem is lid driven cavity flow. An implicit finite volume discretizationtechnique is used in terms of primitive variables for the unstructured code. Unstructured grids are handled with staggered grid arrangement for irregular domainsin 2D. Fractional step method is used as a velocity-pressure coupling.Finally, in addition to these analysis Taylor vortex flows in two different 3Dgeometries and 3D Centrifugal Pump flow analysis are conducted with the aid of variousturbulence models. LES (Large Eddy Simulation), k-epsilon, k-omega turbulencemodels are used. Analysis that are mentioned above is conducted with parallel processingtechnique.