Design optimization of ducted hydrokinetic turbine using CAD-based geometry parametrization*

Previous research suggests that conditioning and accelerating the fluid flow with a duct can improve the hydrodynamic efficiency of a hydrokinetic turbine. Following our previous work [https://arxiv.org/abs/2307.03248] on the topic, we perform a new design optimization study adopting a  CAD-based geometry parametrization method. In particular,  the ducted turbine geometry is generated using Engineering Sketch Pad (ESP), an open-source CAD package.  This parameterization allows us to effectively manipulate the thickness of the duct and a hub with varying diameters, both desirable features considering manufacturing issues. Our gradient-based optimizations leverage an open-source package, DAFoam, which provides both a steady RANS solver and an adjoint solver for flow and sensitivity analysis, respectively. The hydrodynamic efficiency improvement will be demonstrated by comparison to a standard unducted turbine.