Depending on the increase of energy demand in the world, the number and capacity of hydraulic turbines are increasing day after day. Most of the hydraulic turbines are Francis type so, operation and maintenance of Francis turbines is an important issue. On the contrary to thermal power plants, hydraulic turbines mostly operate far from their best efficiency point because of the flexibility in the energy market. This results in flow separation and vortex rope formation in fluid which led to noise and vibration during operation. This study is related with the fluid flow modeling in Francis turbine draft tubes.