Unsteady Hydrodynamic Calculation and Characteristic Analysis of Voith–Schneider Propeller with High Eccentricity

To analyze the hydrodynamic performance of the Voith–Schneider Propeller (VSP) under high eccentricity (e = 0.9), open-water performance numerical calculations were conducted for the VSP at different eccentricities. The results were compared with experimental data, revealing significant discrepancies at high eccentricity. Analysis identified that during the experiment, the VSP blades did not strictly move according to the prescribed “normal intersection principle” when passing near the eccentric point, which was the primary cause of the errors between the calculation and experiment. Further research demonstrated that when the blades pass near the eccentric point, both the individual blade and the overall propeller exhibit strong unsteady pulsation phenomena. The characteristics of these unsteady forces become more pronounced with increasing eccentricity. For the VSP under high eccentricity (e = 0.9), different Blade Steering Curves near the eccentric point were designed using a parametric method. The hydrodynamic performance of the VSP under these different curves was compared. The study demonstrates that rationally optimizing the motion of blades is a key approach to improving their hydrodynamic performance. At J = 2.4, the adoption of Opt-5 enables a 4.67% increase in thrust, a 25.19% reduction in thrust pulsation, a 12.74% reduction in torque, an 81.94% reduction in torque pulsation, and a 19.95% improvement in efficiency for the VSP.