In this chapter, various kinds of vortex in the hydroturbines are briefly
introduced with a focus on the swirling vortex rope in Francis turbine and the vortex in
the vaneless space of the reversible pump turbine. The vortex induced pressure fluctuation
and vibrations are initially demonstrated based on the on-site measurement in the
prototype power stations. Then, influences of the vortex in the upstream on the flow status
in the downstream are discussed. Finally, detailed characteristics of the swirling vortex
in the draft tube section of the hydroturbines are demonstrated based on the plenty of
examples together with the aid of a quantitative swirl number analysis.
Keywords: Hydroturbines, Pressure fluctuations, Vibrations, Vortex, Vortex rope.
