Angle of attack impact on flow characteristics around finite-length rotating columns

The finite-length rotating column has been extensively studied because of its importance in various fields, such as marine and aerospace. In this study, the hydrodynamic performance of a finite-length rotating column with two free ends at different angles of attack is investigated using a large eddy simulation method. The effects of various geometries (including an equal-section cylinder and a variable-section truncated cone), incoming flow velocities, column rotation speeds, and angles of attack on the lift and drag characteristics and wake field of the rotating column are analyzed. The results reveal that a free end creates a concentrated tip vortex, which shortens the effective length that can generate the Magnus effect. Across different geometries and computational conditions, a relatively consistent lift coefficient is found for angles of attack from 60 degrees to 120 degrees, with the cone design significantly reducing the drag by approximately 10% for angles of attack from 120 degrees to 150 degrees. These findings provide valuable insights into the practical application of finite-length rotating columns. Specific recommendations for optimizing the design of these columns are suggested, including choosing appropriate geometries and considering the effects of incoming flow velocities and column rotation speeds.