Numerical study of turbulent flow around a rotating cylinder with Backward-facing steps

초록

Erosion-corrosion in a pipe system often occurs at fittings, valves, and weld beads where flow separation and reattachment yield high turbulence intensity. Thus identifying their correlations would be the first step towards resolving the erosion-corrosion problems associated with industrial applications. We proposed that a rotating cylinder with surface roughness (two backward-facing steps periodically mounted on a circular cylinder) be an economical and tractable tool which can generate extreme flow conditions for erosion-corrosion study. In this work, DNS has been carried out for turbulent flow around the same rotating cylinder as our experimental apparatus. The numerical result shows that a region of intense turbulence intensity and high wall-shear stress fluctuation is formed along the cylinder surface in the recirculating region behind the step, where high mass-transfer capacity is also experimentally observed. Since corrosion is mass-transfer controlled, our finding sheds light on the direction of future corrosion research.