Experimental and numerical studies on moderate-(Formula presented) aerodynamics of cambered thick wingsails in crescent shape

Journal article, 2026

For wind-assisted ship propulsion (WASP), wingsails with cambered sectional profiles like crescent-shaped ones have shown great potential considering high thrust generation. However, there have been few experimental and numerical studies to address such wingsails at moderate Reynolds numbers ((Formula presented) ), of which knowledge is important for guiding fast design. In this study, the aerodynamics of a crescent-shaped wingsail at a range of moderate (Formula presented) is investigated in isolated and triple-sail situations. Wind tunnel tests and high-fidelity computational fluid dynamics (CFD) simulations, which use the improved delayed detached eddy simulation (IDDES) approach, are conducted. The wingsails of two aspect ratios ((Formula presented) and (Formula presented) corresponding to semi-retracted and fully expanded sails in practice) are analyzed at the angles of attack from 0^∘ to 90^∘[jls-end-space/], and (Formula presented) from (Formula presented) to (Formula presented). In addition to general aerodynamic characteristics, a specific crisis of the aerodynamic forces is found at the angle of attack of 15^∘ when (Formula presented) is reduced to (Formula presented), which does not exist in conventional NACA-profile wingsails. When triple wingsails are arranged in a row, the velocity fields between the sails interact, although the vortex patterns in their wakes remain similar. This interference leads to significant redistribution of the aerodynamic forces between the wingsails in the arrangement. The total thrust from the triple wingsail arrangement under the side-wind condition is close to three times the thrust of a single wingsail.