To study the characteristics of the rotating vortex rope (RVR) in the draft tube at different operation conditions of a Francis turbine. During this study period, the validation of the numerical results will be carried out with the available experimental data. This includes the study of vortex excitation characteristics and RVR pressure pulsations at various locations within the draft tube, with the aim to understand the RVR flow characteristics in detail. The analysis also includes the study of fluid-structure interaction so as to come up with appropriate reasoning for the need of optimization of the draft tube in order to overcome the adversity of the RVR.

To optimize the flow performance within the draft tube by introducing new set of guide vanes in the draft tube with the objective to minimize the adverse effects of the vortex rope. This objective is sub-divided into three major categories:

• Design of the guide vane (GV) set for the draft tube: The emphasis will be mostly on the profiling and the orientation of the GV system in the draft tube based of the RVR analysis in first half of the project.
• Fabrication and Implementation: Based on the numerical analysis of above mentioned objective, the design will be used for the practical implementation on the test rig in NTNU, Norway.
• Experimental and computational validation of the optimized draft tube design at various operational loads.