Abstract: A draft tube for discharging fluid from a hydraulic turbine is disclosed as having a draft tube wall surrounding a discharge passage which diverges from a turbine runner to a discharge opening. The draft tube includes a first region downstream of the runner which has a rate of divergence less than that at which boundary layer separation occurs. A second region, downstream from the first region, has a rate of divergence greater than that at which boundary layer separation normally occurs. The draft tube wall surrounding the second region is provided with a plurality of orifices. A plurality of nozzles are provided on the draft tube wall surrounding the first region. Piping connects the orifices with fluid inlets of the nozzles. The nozzles have fluid outlets which communicate with the discharge passage in the first region and open away from the turbine runner. Fluid along the wall in the second region passes through the orifices and piping and into the nozzles.