Effect of the heave plate's diameter on the transitional motions of a straked marine circular cylinder under different marine conditions

This numerical study investigated the influence of the heave plate's diameter on the amplitude of the transitional motions of a marine circular cylinder (MCC) with a low aspect ratio under the marine current and regular waves. Due to the experimental model of the straked MCC, different diameters of the circular heave plate were chosen to be installed at the keel of the 3-straked MCC. In this numerical study, the diameter of the heave plate varied from 1.2 to 1.6 DMCC, while other parameters, such as reduced velocity (VR), Reynolds (Re) number, and Froude number, were kept constant. In this study, the transitional motions, including surge, sway, and heave, were analyzed. The results showed that increasing the heave plate's diameter decreased the amplitude of the transitional motions in both marine current and regular waves. Also, the finding revealed that the heave plate not only reduced the amplitude of the heave motion but also decreased the amplitude of surge and sway motions. Moreover, the outcomes indicated that the heave plate's diameter increased by approximately 20%–40% more than the MCC's diameter. This caused the smaller amplitude of the transitional motions under both marine currents and regular waves.