Numerical study of rotating helical groove for drag reduction

The surface structure plays an important role in fluid flow and vortex dynamics. To investigate the mechanism of drag reduction and flow characteristics under the influence of the helical groove structure and rotational conditions, this study conducts a systematic numerical simulation on helical grooves at Reynolds numbers Re = 50–200, rotation rates α = 1–3, and groove angles θ = 0°−80°. The results show that the helical groove structure affects the vortex shedding pattern. Under stationary conditions, the helical groove with θ = 45° exhibits the lowest average drag coefficient at Re = 50, 100, 150, and 200, with a 20% reduction compared to the smooth cylinder at Re = 150. At Re = 200, the average drag coefficient of the helical groove at α = 1 is 10.2% lower than that of the smooth cylinder, and at α = 3, it is 89.04% lower than that of the stationary smooth cylinder. These results indicate that the helical groove structure exhibits excellent drag reduction performance under both stationary and rotating conditions.