Sailboat Keel Optimization

Abstract

High-level sport serves as a powerful driver for research, particularly in the fields of aerodynamics and hydrodynamics. This work presents a multi-level optimization methodology for sailboat keels, aimed at reducing hydrodynamic drag during racing conditions.

The optimization strategy consists of two complementary phases. In the first phase, a two-dimensional optimization defines the optimal fin section profile using Bezier curves parameterized with 8 design variables. This process employs modeFRONTIER as the optimization platform, Matlab for workflow management, and X-Foil for aerodynamic analysis. In the second phase, a three-dimensional optimization determines the complete fin-bulb system geometry through 21 design parameters with a constraint on bulb volume. Three-dimensional CFD simulations were performed using StarCCM+ on an HPC cluster with 1024 cores, while parametric CAD modeling was carried out in CATIA V5.

The objective function balances performance across different sailing points: F_obj = 0.4·Cd_downwind + 0.6·Cd_upwind, assigning greater weight to upwind conditions, which are typically more critical for overall racing performance.