Abstract: The actuator disc（AD）model combined with the CFD method has the advantage of being computationally less expensive and more efficient than the CFD advective mesh technique. The OpenFOAM open source software is used and the thrust T is uniformly loaded into the AD as an additional source term for the body force. The flow field is analyzed for three cases:free zone,single turbine and array turbine at top speed ratio（TSR）5.5. The results show that at the upstream of the incoming flow,the three flow velocity profiles coincide and the flow velocity increases in the same trend. When the water is at the front of the AD,the AD acts as a drag on it,resulting in a significant drop in flow velocity. At the wake,in the upstream of the array turbine,kinetic energy is exchanged between the turbine wake and the downstream turbine flow field on both sides of the parallel,causing the wake to recover at a greater rate than the single turbine wake. However,at the horizontal cross-sectional velocity at the centre of the rotor,the wake recovery is severely under-recovered in both the single turbine and the array turbine. The reason for this is that due to the interference of the wake,the incoming flow velocity from the downstream turbine is continuously reduced and the amount of energy that can be absorbed and transformed decreases,and the wake cannot be recovered.