Modeling the impact of a vortex ring on a solid surface

The effect of interaction between a vortex ring and a solid surface is experimentally and theoretically investigated. Analytical formulas are provided that allow describing the pressure pulses arising when the vortex ring passes near the flat surface. The forms of pressure pulses are compared with those recorded in the experiment. The results may be utilized to predict the off-design regimes of a hydraulic turbine; such regimes are characterized by aperiodic high impacts in the hydraulic turbine's circuit behind the runner.