Flettner Rotors With Flexible Perovskite Photovoltaics for Hybrid Wind–Solar Ship Propulsion: A Feasibility Assessment

A hybrid renewable‐energy concept combining wind‐assisted ship propulsion (WASP) with flexible perovskite photovoltaic (PPV) coatings is examined as a preliminary system‐level feasibility assessment for long‐distance commercial shipping. Rotor sails, rigid wing sails, and suction sails are compared using a weighted multicriteria framework. Rotor sails obtain the highest baseline score (4.0/5), although a weighting sensitivity analysis shows that the ranking is preference‐dependent and can favor wing sails when fuel‐saving performance is strongly prioritized. For a representative 300 m container ship with three 30 m high, 5 m diameter rotors, the reduced‐order model gives 137.8 kN lift and 1.38 MW gross equivalent propulsion power at an apparent wind speed of 10 m s ⁻¹ and lift coefficient C _L  = 5. A literature‐based rotor‐drive‐power screening range of 0.135–0.338 MW reduces the indicative net propulsion contribution to 1.04–1.24 MW, corresponding to a 2.60%–3.11% main‐engine power offset under the favorable baseline alignment. Sensitivity analyses quantify the effects of C _L , apparent wind angle, and drag. A fully active 1413.7 m ² PPV surface at 20% nominal efficiency and 250 W m ⁻² irradiance gives 42.4 MWh over 25 days only as an ideal upper bound; applying an illustrative effective collection factor of 0.25–0.50 reduces the screening range to 10.6–21.2 MWh. The two‐dimensional CFD analysis provides a mesh‐verified comparison of smooth and geometrically enlarged rotor configurations. Systematic mesh refinement and grid convergence index (GCI) analysis were used to quantify numerical uncertainty, while direct integration of total surface traction and aerodynamic moment provided force and torque comparisons. The 2% radial enlargement increased the total streamwise‐force magnitude by ~2.33%, the transverse force by ~2.67%, and the aerodynamic torque by ~2.94%. These results represent a controlled geometric sensitivity assessment rather than a direct prediction of the aerodynamic effect of a physical PPV laminate. The study therefore establishes feasibility bounds, quantified aerodynamic sensitivity, and validation requirements rather than validated voyage‐level performance predictions.