CFD simulation of a horizontal axis hydrokinetic turbine

Abstract

This study presents three-dimensional full transient numerical simulations of a horizontal axis hydrokinetic turbine, HAHT with particular emphasis on the analysis of its hydrodynamic characteristics. Hydrokinetic turbine performance is studied using a time-accurate Reynolds-averaged Navier-Stokes (RANS) commercial solver. A physical transient rotor-stator model with a sliding mesh technique is used to capture changes in flow field at a particular time step. A shear stress transport (SST) turbulence model has been employed to model the turbulent features of the flow. The studied rotor has three blades, based on NACA4412 airfoil. Two operation conditions have been considered: shaft parallel to the incoming flow (SP configuration) and shaft inclined an angle α around 30o regarding the main stream (SI configuration). As a result, the decrement of the hydrodynamic performance of the turbine with the inclined axis is quantitatively evaluated regarding that of the parallel axis. Moreover, a preliminary study of the vorticity dynamics in the wake of the inclined rotor is performed.