Qeshm channel between the Persian Gulf and Oman Sea with a maximum tidal current velocity of about 2 m/s is unsuitable for installing conventional tidal turbines. This study aims to introduce a new turbine with semi-cylinder deflectors, which is added to a Savonius tidal turbine to make feasible power extraction from this low-speed tidal current. For this purpose, Computational Fluid Dynamics analysis is done on the Savonius turbine with 2,3, and 4 blades in two cases (with and without deflectors). The results show an increase in power coefficient (CP) to 0.38 at an optimum TSR of 0.68 for two-blade Savonius Rotor by implementing semi-cylinder deflectors. In comparison, the maximum CP is 0.14 for a two-blade Savonius rotor without deflectors. Power coefficient decreases by increasing the number of blades in rotors with obstacles. CP has an upward trend by increasing the speed of water flow in the absence of deflectors. However, CP has an upward trend till 1.5 m/s current speed and after that has a downward trend in rotors with deflectors. As a general result, the Savonius turbine with semi-cylinder deflectors is very consistent with the conditions of the Qeshm channel, in which the tidal current speed is always fewer than 2 m/s.