Structural and hydrodynamic characterization of a NACA 0009 hydrofoil by finite elements

Simulation-based design optimization (SBDO) assists the designer in the design process of complex engineering systems. Design goals and requirements of the SBDO are often multidisciplinary, such as in aerial (e.g. aerody- namics, structures, flight mechanics, aeroacoustics), ground (e.g. aerodynamics, structures, engines) or maritime (e.g. hydrodynamics, structures, propulsion) applications. Multidisciplinary design optimization (MDO) refers to the identification of the best solution with respect to optimality criteria, whose definition involves a number of disciplines mutually coupled and interconnected. Deterministic MDO methods have been successfully applied in ship design for fluid-structure interaction (FSI) applications (Campana et al, 2006), including composite materi- als (e.g. Liu and Young 2007; Volpi et al 2015). Realistic applications are affected by uncertainty, both on the operating (e.g. speed) and environmental (e.g. sea state) conditions. Therefore, uncertainty quantification (UQ) methods (He et al 2013; Mousaviraad et al 2013; Diez et al 2014) are required in the optimization process, leading to multidisciplinary robust design optimization (MRDO) formulations (e.g. Diez et al 2012; Leotardi et al 2014). Within this context, the objective of this work is the preliminary structural and hydrodynamic characterization of a NACA 0009 hydrofoil, including a comparison with numerical and experimental data from Zarruk et al (2014). This represents a first step towards a simulation-based MRDO of the hydrofoil. The characterization is performed with numerical (structural and hydrodynamic) simulations by finite element method (FEM). A grid convergence analysis using different shape functions is presented to determine the dry eigenfrequencies and modes; a comparison with experimental data is shown. Wet modes and eigenfrequencies are computed using a structural- acoustic multi-physics approach. A comparison with a 2D potential strip-theory method (the results are taken from Zarruk et al 2014) is also shown. The hydrodynamic characterization is performed, including grid convergence analysis and comparison with experimental data. The numerical simulations are performed with the commercial finite element code COMSOL MultiphysicsTM.