Numerical Analysis of Flow Around Cylinders at Trans-Critical Reynolds Numbers with and Without Surface Roughness

• Autores: A.A.S. Burger, H.C.R. Reuter
• Localización: Journal of the International Association for Shell and Spatial Structures, ISSN-e 1996-9015, ISSN 1028-365X, Vol. 57, Nº. 1, 2016 (Ejemplar dedicado a: Special Issue on Cooling Towers), págs. 35-47
• Idioma: inglés
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  • This paper investigates the flow and pressure distributions around cylinders at trans-critical Reynolds numbers by means of computational fluid dynamics (CFD) using the Realizable k-ε Turbulence Model. A steady state two dimensional Fluent® CFD model is developed and the effects of changes to surface roughness, cylinder rotation and an air viscosity adjustment factor at the cylinder surface on the static pressure distribution around a cylinder are investigated numerically. The main objective is to determine which parameter is best suited for the rigorous adjustment of the pressure distribution to simplify the modelling of surface roughening by means of wind ribs. A calibration method is proposed with which the required value of the selected parameter can be determined from numerical simulations or experimental measurements on a flat plate to be able to model wall shear and air flow patterns more accurately. The proposed method will ultimately allow for improved sensitivity analysis and modelling of particularly natural draft cooling tower performance under wind conditions with and without meridional ribs on the outer shell surface.