Direct numerical simulation has been carried out for turbulent flow set up by a rotating cylinder with two backward-facing steps axisymmetrically mounted in the circumferential direction. This flow geometry creates a qualitatively similar flow pattern as observed near a sudden pipe expansion or a plane backwardfacing step, characterized by flow separation and reattachment. A region of intense turbulence intensity and high wall-shear-stress fluctuations is formed in the recirculating region downstream of the step, where high mass-transfer capacity was also experimentally
observed. Since corrosion is frequently mass-transfer controlled, our findings put forward this apparatus as a useful tool for future corrosion research.