A Shape Optimization Pipeline for Marine Propellers by means of Reduced Order Modeling Techniques

TL;DR

The paper develops a shape optimization pipeline for marine propellers using non-intrusive reduced-order models built from high-fidelity OpenFOAM URANS simulations. It introduces two ROM strategies: a standard ROM with full-blade mesh data and a fast ROM using quadrature-point data, both leveraging POD for reduction and RBF-based interpolation for parameter-to-solution mapping. A genetic algorithm explores four blade-geometry deformation parameters to maximize propeller efficiency, with extensive offline data collection (216 blade variants) and online ROM-based predictions achieving substantial speedups over full-order simulations. The study shows comparable accuracy between ROMs and FOMs, highlights the trade-offs between unconstrained and constrained optimization, and argues for the practical viability of ROM-driven design in naval applications. The approach is modular, enabling extension to other fluid-structure optimization problems and offering clear pathways for further performance enhancements and sensitivity analyses.

Abstract

In this paper, we propose a shape optimization pipeline for propeller blades, applied to naval applications. The geometrical features of a blade are exploited to parametrize it, allowing to obtain deformed blades by perturbating their parameters. The optimization is performed using a genetic algorithm that exploits the computational speed-up of reduced order models to maximize the efficiency of a given propeller. A standard offline-online procedure is exploited to construct the reduced-order model. In an expensive offline phase, the full order model, which reproduces an open water test, is set up in the open-source software OpenFOAM and the same full order setting is used to run the CFD simulations for all the deformed propellers. The collected high-fidelity snapshots and the deformed parameters are used in the online stage to build the non-intrusive reduced-order model. This paper provides a proof of concept of the pipeline proposed, where the optimized propeller improves the efficiency of the original propeller.

Figures (16)

• Figure 1: Pipeline of the shape optimization.
• Figure 2: Generic structure of a propeller.
• Figure 3: Radial view of a propeller's blade. The figure on the left shows the original cylinder sections of a blade, where $R$ is the propeller radius and $r_0$ is the hub radius. The figure on the right represents the projections of the corresponding sections on a flat plane.
• Figure 4: \ref{['subfig:section_params']}: Graphical definition of the parameters of a blade section: chord length, thickness, and camber corresponding to the preset chord percentages. \ref{['subfig:section_def']}: Example of deformed blade root section.
• Figure 5: Graphical view of three deformed blades.