Numerical optimisation of a ship wind-assisted propulsion system using blowing and suction over a range of wind conditions

Abstract

A Kriging surrogate model and a genetic algorithm are used to optimise the geometry of a ship wind assisted propulsion system (SWAP). The SWAP device is an actively controlled aerofoil mounted vertically on the deck of a ship in order to produce a forward propulsive force from the wind. The SWAP concept uses a circulation control system which employs both blowing from the leading edge and suction from the trailing edge. The aerodynamic parameters of the sail are found using a computational fluid dynamics (CFD) model validated against experimental data for a similar system, the coflow jet aerofoil. Further application of Kriging models is used to predict maximum lift coefficients for multiple freestream velocities, ensuring that the optimised device offers robust performance and low sensitivity to expected variations in wind speed. The maximum achievable lift coefficient was found to be 13.17% greater than for the baseline aerofoil over a range of wind speeds from 8–12 m/s.