Aortic valve stenosis can trigger regions of turbulent flow downstream of the aortic valve. This disturbed blood flow in this region can cause tissue damages due to increased levels of turbulent shear stress. The aim of the present work was to investigate the effect of aortic stenosis on turbulence parameters of the blood flow over flexible leaflets of aortic valve. In this study the turbulent flow was simulated numerically using k-epsilon realizable model. The interaction between fluid and structure fields was applied using an implicit iterative method. To characterize the turbulent intensity, turbulent kinetic energy was computed. The results show that the levels of turbulence increases with more severe stenosed valves. The results also revealed that the flexible behavior of the leaflets of the aortic valve can also disturb the flow which can produce regions of turbulence downstream of the aortic valve.