Investigations Of Pressure Pulsations In A Model Of Draft Tube Of Hydraulic Turbine Caused By Vortex Rings

Current work is devoted to experimental investigations of behavior of precessing vortex rope in a draft tube model of hydraulic turbine. We used combination of stationary and freely rotating swirlers as a hydro turbine model. Such construction provides velocity distribution on the draft tube inlet close to distribution in natural hydraulic turbines operated at non-optimal conditions. The phenomenon of precessing vortex rope reconnection with further formation of vortex ring was founded in this experimental research using high-speed visualization technique. Synchronization of highspeed visualization and pressure measurements allowed us to relate pressure shock on the draft tube wall with vortex ring moving along wall.