Aksoy, Muharrem HilmiKurtulmus, NazimIspir, MuratGoktepeli, Ilker2026-02-102026-02-1020260029-80181873-5258https://doi.org/10.1016/j.oceaneng.2026.124281https://hdl.handle.net/20.500.13091/12958Flow structures over circular cylinders have been widely investigated due to their practical importance and the complexity of wake interactions. In this study, combined passive and active flow control strategies have been examined for rotating cylinders with surfaces having dimples/protrusions at a Reynolds number as Re = 2 x 103. Particle Image Velocimetry (PIV) measurements have been conducted for rotation rates ranging from alpha = 0 to alpha = 1.26 to explore modifications in wake topology for different circumferential angles ((3) between 15 degrees and 60 degrees. For the stationary bare cylinders, symmetric recirculation regions including counter-rotating eddies have been observed, whereas rotation caused the separated region to contract, shifted and lost its symmetry. Dimples/ protrusions, even without rotation, altered shear layer development with effects varying according to the circumferential angle. When rotation was applied, the modified surfaces produced notable changes compared with that of the bare cylinder, including reduced negative-velocity regions and more rapid momentum recovery. The time-averaged vorticity distributions indicated the diminished vortex intensity, while the periodic organization of the shedding became less distinct at higher rotation rates. Turbulence kinetic energy and Reynolds stress correlations presented that surface modifications, particularly at (3 = 30 degrees, 45 degrees and 60 degrees, enhanced shear layer energization, delayed flow separation and disrupted wake symmetry at alpha >= 0.84. The combination of rotation and surface texturing is therefore effective in reshaping wake dynamics and attenuating large scale vortex structures, offering practical implications for flow control applications.eninfo:eu-repo/semantics/closedAccessCircular CylinderPIVRotationSurface ModificationsWake RegionArticle10.1016/j.oceaneng.2026.124281