Wells turbines dynamic simulation using cfd and a lumped parameter model

The hydrodynamics and aerodynamics of oscillating columns systems have been largely studied both experimentally and numerically, especially through laboratory facilities which focused either on OWC or power unit performance, usually aWells turbine. For the latter, a common simplification is made by substituting the periodic wave motion with the alternative motion of a piston in a chamber that is connected to the duct that hosts the turbine. This setup led to detailed studies on the difference between turbine performance during acceleration and deceleration, usually attributed to a hysteretic behavior of the turbine. This work demonstrates, using both CFD and a lumped parameter model, that the OWC hysteresis is caused by compressibility effects in the air chamber and not, as previously assumed, by an aerodynamic hysteresis of the turbine.