抄録
In a circular cylinder with uniform flow, a sudden decrease in the drag force occurs at a high Reynolds numbers; however, it is known that the same phenomenon occurs at a lower Reynolds number in the case where there exist grooves or roughness on the circular cylinder surface. To clarify the flow characteristics around a circular cylinder in the case of changing the shape of grooves, numerical analysis was performed by applying the RNG k-ε turbulent model. The shapes of the grooves used triangulated and curved section. The results showed that the separation point for a circular cylinder with large curved sectional grooves shift to the most downstream side and the drag coefficient becomes the smallest among circular cylinders with grooves.
