Axial-flow hydrokinetic turbine performance prediction and wake reproduction in turbulent flow conditions using a simplified turbine model*

Aiming at obtaining good performance prediction for each individual turbine in farm at a practical computational cost, a simplified model for hydrokinetic axial-flow turbine, the Effective Performance Turbine Model (EPTM-AFT), has been previously developed based on the non-uniform actuator disk concept, which has been proven to correctly reproduce the mean drag and power of a turbine in uniform and clean inflow (Bourget et al., 2018). However, turbines deployed in farms with realistic flow conditions are generally exposed to different types of flow perturbations. Particularly, small-scale inflow fluctuations significantly promote the tip vortex instability and accelerate the wake recovery, which further affects the performances of downstream turbines. In this study, the EPTM-AFT model is tuned and tested in a characteristic turbulent flow environment using 3-D Reynolds-Averaged Navier-Stokes simulations. The comparison with blade-resolved Delayed Detached-Eddy Simulation shows that the EPTM-AFT model produces accurate predictions for mean turbine performances and wake properties.