Shape optimization is a challenging task in many engineering
fields, since the numerical solutions of parametric system may be
computationally expensive. This work presents a novel optimization
procedure based on reduced order modeling, applied to a naval hull
design problem. The advantage introduced by this method is that the
solution for a specific parameter can be expressed as the combination
of few numerical solutions computed at properly chosen parametric
points. The reduced model is built using the proper orthogonal
decomposition with interpolation (PODI) method. We use the free form
deformation (FFD) for an automated perturbation of the shape, and the
finite volume method to simulate the multiphase incompressible flow
around the deformed hulls. Further computational reduction is done by
the dynamic mode decomposition (DMD) technique: from few high
dimensional snapshots, the system evolution is reconstructed and the
final state of the simulation is faithfully approximated. Finally the
global optimization algorithm iterates over the reduced space: the
approximated drag and lift coefficients are projected to the hull
surface, hence the resistance is evaluated for the new hulls until the
convergence to the optimal shape is achieved. We will present the
results obtained applying the described procedure to a typical
Fincantieri cruise ship
