CFD simulations of the helicoidal vortex rope with transient boundary conditions

Supervisor :  Prof. François Avellan
Assistant : 
Theme :  CFD & Hydroacoustic

The swirling flow leaving the runner in the draft tube of a Francis turbine may act under given conditions as an excitation source for the whole hydraulic system. In part load conditions, the frequency of the helicoïdal vortex rope can match with one of the system’s eigenfrequency which yields to resonance phenomena. In that case an acoustic standing wave occurs in the hydraulic system. The aim of this project is to perform a CFD simulation of the vortex rope with transient boundary conditions corresponding to this acoustic standing wave. The student will compare simulation results between transient and stationary boundary conditions in order to assess the influence of this acoustic standing wave on the 3D flow in the draft tube.