Integrated Investigation of Flow-Induced Drag Reduction in Stepped Cylinders at Supercritical Reynolds Numbers

The aerodynamic characteristics of plain and stepped cylindrical constructions are crucial in architectural design, marine applications, and structural engineering. The present study examines the impact of stepped-cylinder geometry on drag and wake characteristics under supercritical flow conditions. Experiments were performed on three stepped cylinders (Model 1, 2, 3) and one plain cylinder in a wind tunnel at Reynolds numbers between 1.0 × 106 and 1.4 × 106. Static probes quantified pressure distributions around a stepped cylinder, whereas numerical simulations employing the RANS methodology with a k-ε turbulence model validated the results. These results indicate that step configurations substantially influence pressure distribution, drag coefficient (CD), and wake region. Of the evaluated geometries, Model 3 had the highest efficacy in drag reduction and wake suppression. These findings offer insights into flow control strategies for applications involving bluff bodies at high Reynolds numbers.