High-fidelity Coupled Hydrostructural Optimization of a 3-D Hydrofoil

摘要

With recent advances in high performance computing, computational fluid dynamics (CFD) modeling has become an integral part in the engineering analysis and design of marine vessels and propulsors. A previously developed 3-D compressible Reynolds-averaged Navier-Stokes (RANS) solver extended to solve for nearly incompressible flows, coupled together with a structural finite element solver, is used for the high-fidelity hydrostructural optimization of a 3-D hydrofoil. The coupled hydrostructural solver is validated against the experimental measurements of a tapered hydrofoil from Zarruk et al. [1]. The coupled hydrostructural tool has been integrated with the adjoint method to enable efficient high-fidelity, optimization with large number of shape design variables. The coupled hydrostructural optimization study for an unswept, cantilevered, tapered 3-D NACA 0009 hydrofoil made out of solid aluminum was carried out. A total of 210 shape design variables were used in the optimization study, with constraints on the lift coefficient (C_L), cavitation number, and maximum stress (based on the fatigue strength of aluminum). The hydrostructurally optimized foil results in an increase in efficiency (C_L/C_D) of 12.4%, a reduction in foil mass of 7.3%, and an increase in cavitation inception speed by 45%, over the original NACA 0009 hydrofoil, while satisfying the cavitation constraint and the maximum stress constraints.