Three-dimensional numerical study on flow control of two-phase flow around a cylinder with an auxiliary miniature cylinder

In ocean engineering, studying the phenomena of flow separation, vortex shedding, and particle deposition around blunt bodies is crucial, as these factors significantly affect the performance, stability, and lifespan of marine structures. This study, conducted under realistic marine conditions with a Reynolds number of Re = 2.5 × 105, and accounting for gravitational effects, first investigates the impact of installing auxiliary miniature cylinders at the front edge of the primary cylinder with different gap ratios, aiming to identify the optimal gap ratio. Subsequently, trailing-edge miniature cylinders are added for comparative analysis. This study also explores the effects of vibrating upstream miniature cylinders. Additionally, it examines the influence of auxiliary miniature cylinders on particle distribution in the wake region under particle-laden flow. The results indicate that miniature cylinders at specific gap ratios significantly reduce the drag and lift coefficients of the primary cylinder, suppress vortex shedding, optimize wake structures, and weaken the horseshoe vortex. While vibrating cylinders reduce vortex suppression, high-frequency vibrations contribute to greater drag reduction. Upstream miniature cylinders reduce the influence of vortex structures in the wake but increase sediment deposition. A dual-cylinder configuration is the most effective method for controlling sediment concentration distribution at the base of the primary cylinder.