Numerično modeliranje toka mikropolarnih tekočin z metodo robnih elementov : doktorska disertacija

slovenian

doktorska dela

2009

Univerza v Mariboru, Fakulteta za strojništvo

In this work the new approach for numerical modeling of a micropolar fluid flow based on a boundary element method is presented. Micropolar fluid flow theory is describing flow of a rheological very complex fluids with structures, which have own rotation. Such a physical behaviour of a fluid is not included in the classical system of Navier-Stokes equations. To simulate micropolar fluid flow with the existing boundary element method based code, additional terms have to be included in the vorticity transport equation together with additional transport equation for microrotation, closing the setof governing equation, written in velocity vorticity formulation. In this work the governing equations of micropolar fluid are derived in differential, integral and discretised form, resulting from the application of the boundary element method. In deriving the numerical algorithm, the domain terms are discretised by means of subdomain technique. The derived numerical algorithm, which presents extension of existing numerical algorithm based on the classical Navier-Stokes equations, is verified through the examples of natural convection in a cavity, flow in a channel and mixed convection of micropolar fluid in a cavity. Computational results for micropolar fluids, obtained by the new numerical algorithm, show good agreement with results of other authors, confirmaing successful implementation of micropolar fluid flow theory into existing boundary element method based numerical algorithm for numerical modeling of flows with use of classical theory of Navier-Stokes equations. Through the work the meaning and importance of new model parameters included in the micropolar fluid flow theory is discused. The results of performed numerical simulations of the micropolar fluid flow show that one can expect significant sensitivity of flow and temperature fields on different micropolar fluid flow parameters. The derived numerical algorithm presents extension of the use of computational fluid dynamics methods based on boundary element method to the field of numerical simulations of micropolar fluids.

08.08.2023