Passive flow control using a detached triangular splitter plate behind a circular cylinder: Effect of spacing ratio

A numerical study is conducted to analyze the flow past a circular cylinder equipped with a detached triangular splitter plate placed downstream at four different spacing ratios. The objective of this investigation is to evaluate a passive flow control method for drag reduction and mitigation of flow-induced vibrations, which are common issues in engineering applications such as underwater pipelines and cables. The reduction of unsteady forces enhances structural stability, extends service life, and reduces fatigue damage. In this passive flow control technique, four spacing ratios (SR=0.25–1.0) are considered. Simulations are performed using an incompressible finite-volume method to analyze the flow dynamics at Reynolds numbers (Re=150, 180, and 200). Compared to the bare cylinder, drag reduction is observed for all spacing ratios and Reynolds numbers. Maximum drag reductions of 17.68%, 19.42%, and 23.98% are achieved at a spacing ratio of (SR=1.0). At (SR=0.25), drag reductions of 11.27%, 11.19%, and 15.0% are obtained for Reynolds numbers (Re=150, 180, and 200), respectively. As the spacing ratio increases, a 10.36% reduction in the Strouhal number is observed at (SR=0.25) compared with the bare cylinder, while the maximum reduction of 30.05% occurs at (SR=1), indicating that vortex shedding is progressively suppressed with increasing spacing ratio.