Abstract
Throughout recent history, electricity has been a driving force behind human growth and prosperity. In this paper, Tethered Undersea Kite (TUSK) systems, as an alternative to the fixed hydrokinetic turbine, are examined. To acquire ocean current energy, TUSKs move perpendicular to the motion of the water with a turbine mounted under their wings. The first part of this article discusses kite flight dynamics, in which the yaw, roll, and pitch angles are calculated along the kite's trajectory. In the second part, a ducted turbine is designed and its motion inside the turbulent ocean current is numerically analyzed. The accuracy of the computational simulation utilizing k - w SST turbulence model is validated by deploying Blade Element Momentum (BEM) theory. A parametric study is performed to investigate the effect of the tip speed ratio on the performance of the designed turbine. Eventually, the apparent velocity of the kite is calculated at eight specific position points along the kite's trajectory, then the corresponding power is obtained in a quasi-steady state simulation. A power output of 383 kW, average over one cycle, is achieved while the kite moves along its optimal trajectory. The results also show that the power coefficient exceeds the BETZ limit (i.e. 59.3 %) due to the presence of the duct which in turn generates vortices followed by a low-pressure flow region.