Hydropower is a clean and renewable source of energy which is widely used to generate
electric power and stabilize the power grid. It can respond quickly to any change in demand …

Operational flexibility of hydraulic turbines is impeded by the vortex breakdown
phenomenon. The phenomenon, a consequence of instability in vortical flows in general …

Abstract Rotating Vortex Rope (RVR) resulting from flow instabilities inside draft tube affects
the hydraulic turbine's efficiency and wear. Among the passive and active RVR mitigation …

Precessing vortex rope (PVR) plays a key role in inducing hydraulic resonance in Francis
turbines operating at partial load, possibly degrading power plant stability and availability …

We report on the experimental study of a precessing vortex core (PVC) in an air model of a
Francis turbine. The focus is placed on the modal decomposition of the PVC that occurs in …

During the load rejection transient process of the prototype pump turbine units, the pressure
fluctuations of the entire flow passage change drastically due to the rapid closing of guide …

This work investigates the unsteady pressure fluctuations in two prototype Francis turbines
during load variation and start-up. Although hydraulic turbines are expected to experience …

This paper focuses on the generation of twin vortex rope in the draft-tube elbow of a Francis
turbine at deep part-load operation through analyzing the results of model tests along with …

Transient processes that occur in pumped storage power plants can cause high-pressure
conditions, which in turn can result in vibrations in the pump–turbine structure and even …

Nowadays, pump-turbine units have to experience multiple start-stops every day to balance
the power production and consumption on the grid. During the transient process of turbine …