Objective   The cycloidal propeller is a special propeller which generates thrust by means of profiled blades that protrude from the hull of the vessel and rotate around a vertical axis, allowing precise and stepless thrust generation. It is necessary to study the hydrodynamic performance of cycloidal propeller in open-water and hull wake conditions.

  Methods  By analyzing the operating principle of the cycloidal propeller, a formula for the multiple motion laws of the blades is derived. The open-water performance of the cycloidal propeller is then calculated using the RANS equations and k - \varepsilon turbulence model based on a sliding mesh. Comparison with the experimental data verifies the accuracy of the hydrodynamic performance prediction method of cycloidal propeller. The propellor's unsteady hydrodynamic performance in a ship's hull wake is also investigated.

  Results  The results show that the force on the cycloidal propeller and singular blade has blade frequency characteristics; the fluctuation amplitudes of the thrust and torque increase with the increase of the advanced coefficient; and the lateral force is significantly affected by the hull wake, while the thrust and torque are slightly affected.

  Conclusions  The results of this study have important reference value for research on blade strength evaluation and blade design optimization.