Fluid-dynamic optimization of tapered bulbs in hydrofoil configuration

Recent attention in sailing has shifted towards foiling boats, which can rise above the free surface of the water in order to reduce the drag force. This is achieved by placing small wings under the boat, which provide a supporting force that allows the boat to rise. These wings consist of two main surfaces: a vertical surface, which is used to counteract the lateral forces of the sail, and a horizontal surface, which is the source of lift. At the junction of vertical and horizontal surfaces, is made a structural connection. This joint, named Bulb, has a tapered shape in order to reduce its disturbance to the flow. The purpose of this master’s thesis is to establish a process for fluid dynamic optimization of the bulb, to improve the efficiency of the whole wing. To accomplish this, an optimization tool employing genetic algorithms has been developed in MATLAB. The tool explores the design space by evaluating a single objective function through fluid dynamic simulations in STAR-CCM+. To complete the work was explored the possibility of performing a second detailed optimization, only for the best geometries screened by the tool, through adjoint shape optimization, embedded in STAR-CCM+. The thesis was carried out in collaboration with the MOREnergy lab from Politecnico di Torino.