Large eddy simulation of a utility-scale vertical-axis marine hydrokinetic turbine under live-bed conditions

We present a coupled large-eddy simulation (LES) and bed morphodynamics study to investigate the impact of sediment dynamics on the wake flow, wake recovery, and power production of a utility-scale marine hydrokinetic vertical-axis turbine (VAT). A geometry-resolving immersed boundary method is employed to capture the turbine components, the waterway, and the sediment layer. Our numerical findings reveal that increasing the turbine tip speed ratio would intensify turbulence, accelerate wake recovery, and increase erosion at the base of the device. Furthermore, it is found that the deformation of the bed around the turbine induces a jet-like flow near the evolving bed beneath the turbine, which enhances wake recovery. Analyzing the interactions between turbulent flow and bed morphodynamics, this study seeks to provide physical information on the environmental and operational implications of VAT deployment in natural riverine and marine environments.