Simulation and Experimental Study of Wing Foils for Wind-Assisted Ship Propulsion in an Atmospheric Boundary Layer and Twisted Wind Flow

Abstract

This thesis investigates the aerodynamic behaviour of sails in a boundary-layer wind tunnel with twisted wind flow. In this context, "twist" refers to the change of apparent wind angle along the sail height caused by the sail's movement within the atmospheric boundary layer. Wind tunnel experiments were carried out at FH Kiel using a NACA 0010 wing, covering a range of wind velocities, twist angles, and a complete sweep of angles of attack from 0° to 180°. Streamwise and transverse velocity measurements resolved the boundary layer and the twisted wind flow of the wind tunnel. CFD simulations using the Reynolds-averaged Naver-Stokes (RANS) code STAR-CCM+ were performed to replicate the experiments and theoretical velocity profiles. The combined analysis revealed the influence of twist, transition, and 3D effects on sail performance. For a representative test case a thrust reduction of 17% was calculated. While the experiments provided physical insights into lift generation and stall, the simulations clarified the sensitivity of CFD to mesh resolution, turbulence modelling, and boundary conditions. A direct comparison of both approaches highlighted areas of agreement as well as systematic deviations, offering guidance for the future application of CFD to wind-assisted ship propulsion.