2016 Volume 68 Issue 1 Pages 63-68
The cavitating vortex rope developing downstream a Francis runner has been numerically studied for two off-design conditions. The first condition is a part load condition and the second a full load condition. The numerical approach selected is the Large Eddy Simulation using the FrontFlow/blue (FFB) software. To compute cavitating flows, the Okita cavitation model is implemented in FFB. The computations were performed on K supercomputer using 1,024 nodes. The mesh size features approximately 120 million elements. For both off-design conditions, the cavitating vortex ropes were qualitatively well reproduced. The shape of the vortex rope and the flow distribution within the diffuser are shown for each flow condition.