An experimental and theoretical investigation of the flow at the outlet of a Francis turbine
runner is carried out in order to elucidate the causes of a sudden drop in the draft tube …

The variable demand of the energy market requires that hydraulic turbines operate at
variable conditions, which includes regimes far from the best efficiency point. The vortex …

We report on experimental study of flow and pressure pulsations in draft-tube of a laboratory
air model of Francis-99 hydro-turbine operating over a broad range of regimes employing a …

Vortex rope causes instabilities in hydro-turbines and marine turbines. It is an important
issue in the utilization of ocean energy. The flow energy dissipation (FED) is one of …

This work is focused on reduction of swirling in cases from hydraulic machinery and, thus,
mitigation of instabilities associated with swirling flow. We study this problem analytically …

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 …

When a hydro turbine deviates from the best efficiency conditions and carries the partial
load, the helical vortex rope appears in the center of the draft tube. It will cause the unstable …

We report on parallel experimental studies of twin vortex ropes in laboratory models of an
elbow and a conical hydroturbine draft tube focusing on the unstable cyclic switch-overs …

The swirling flow exiting the runner of a hydraulic turbine is further decelerated in the
discharge cone of the draft tube to convert the excess of dynamic pressure into static …

When reaction hydraulic turbines are operated far from the design operating regime,
particularly at partial discharge, swirling flow instability is developed downstream of the …