Optimization of ships in shallow water with viscous flow computations and surrogate modeling
Due to shallow water effects, optimization of inland ships is more complex than that of sea-going ships. In shallow water, the ship's nominal resistance, the thrust deduction and the wake fraction will in general increase. The close relation between the hull form design and the exact amount of increase in each of these parameters in shallow water makes the optimization of inland ships extra challenging. A ship that is optimal for deep watermay not be optimal in shallow water. Moreover, the water depth an inland ship encounters can change numerous times along the route. For each change of water depth, the ship's speed also changes because of regulations, or because critical speeds or large squat effects have to be avoided. Therefore, a range of water depths and ship speeds, rather than a single depth and speed, should be considered during inland ship optimization.In this paper, we focus on the optimization of the aftpart of an inland ship. While model tests play an importantrole in ship optimization, they are costly in terms of budget and time, especially if multiple hull forms are to be investigated. Computational Fluid Dynamics (CFD) allows for cheaper analysis of a ship for multiple parametric variations and operating points.