Experimental Investigation of Convergent Flow Disturbances for Performance Enhancement of Vertical-Axis Ocean Current Turbine at Low Current Speed in Indonesia

The ocean current speed in Indonesia is relatively low, but it has a huge ocean current energy potential, around 17.9 GW. However, this potential has not yet been optimally utilized in Indonesia. In this study, the influence of CoFD on the performance of Vertical-Axis Turbines (VAT) at low current velocities is investigated. Experimental methods were used to investigate the VAT without and with CoFD in a mini water tunnel. The investigation started with the distance between the flow disturbances and found that a distance of 0.75 times the diameter (0.75D) results in a maximum turbine power coefficient (C_p mαx) greater than 1 times the diameter (D), respectively 0.404 and 0.199. The self-starting capability was tested from 0-0.29 m/s, and at a minimum speed of 0.06 m/s, CoFD can increase the turbine rotation from 0 rpm (without CoFD) to 12.8 rpm (with CoFD 0.75D). Apart from that, CoFD (0.75D) is also able to increase the torque coefficient (C_t) of the turbine with a maximum value of 0.117 to 0.180 and the power coefficient (C_p) with a maximum value of 0.026 to 0.404. CoFD has therefore significantly enhanced VAT performance, especially at low current speeds, and is suitable for use in Indonesia.