Hysteretic characteristics of the Wells turbine in a deep stall condition

Abstract

In order to make clear the hysteresis behaviour of Wells turbine performance in a deep stall condition, experimental and numerical investigations were made for the hysteretic characteristics of such a turbine in such conditions. The experimental investigation was made by the use of turbine equipment in which a sinusoidal flow condition was simulated. The numerical investigation was made using an unsteady three-dimensional Navier-Stokes numerical simulation. The experimental and calculated turbine unsteady performances show two characteristic hysteretic loops. The counter-clockwise hysteresis loop in the unstalled condition can be associated with the separation on the suction surface near the hub, whereas the clockwise hysteresis loop in the deep stall condition can be associated with the separation on the suction surface near the tip.