Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Cooling tower inlet losses and effective flow diameter under no crosswind conditions and the pressure distribution around a circular cylinder subjected to a crosswind are modelled using CFD. The CFD model used to evaluate the inlet losses is validated with data measured in an experimental cooling tower sector model and data obtained from literature. The effect of different inlet geometries on the inlet loss coefficient and the effective diameter are investigated in order to improve cooling tower inlet designs. CFD models are developed to investigate the pressure distribution around infinite and finite circular cylinders. The infinite cylinder is modelled with a smooth surface and a rough surface so that the results can be compared to experimental data from literature. Ultimately a finite cylinder model with a rough surface is developed and the results are compared to experimental data from literature. / AFRIKAANSE OPSOMMING: Koeltoring inlaatverlies en effektiewe vloei deursnit onder geen teenwind toestande en die drukverdeling rondom ‘n sirkelvormige silinder, onderworpe aan ‘n teenwind, word gemodelleer deur gebruik te maak van “CFD”. Die “CFD” model wat gebruik word om die inlaatverlies te evalueer is gevalideer met data verkry vanaf ‘n eksperimentele koeltoring sektor model. Verder word die “CFD” model gebruik in ‘n ondersoek om te bebaal wat die effek is van verskillende inlaat geometrieë op die inlaat verlies koeffisiënt en die effektiewe diameter sodat die inlaat geometrie van koeltorings verbeter kan word. ‘n “CFD” model word dan ontwikkel om die druk verdeling rondom ‘n sirkelvormige silinder te ondersoek. Die silinder word as oneindig gesimuleer met ‘n glade en ruwe wand sodat die resultate vergelyk kan word met eksperimentele data verkry vanaf literatuur. Die afdeling word afgesluit deur die silinder as eindig met ‘n ruwe wand te simuleer en dan word die resultate vergelyk met eksperimentele data verkry vanaf literatuur.