Experimental and numerical study on seakeeping performance of a benchmark ASD tug in head seas

Abstract

Today’s modern ports are undergoing a wave of digital transformation to achieve higher efficiencies and better management of resources. The automation of harbour tugs are one example of concomitant developments for future-ready smart ports. Automating navigation and vessel operations implicitly requires a digital twin, which can be realized as a maneuvering model that incorporates the hydrodynamic behaviour and response of the tug. With the aim of building a maneuvering model, the present work investigates the seakeeping performance of a benchmark azimuthing-stern drive (ASD) tug using both experimental and numerical means. Experimental tests were performed in a towing tank using a 1:9.78 scale model at Fr = 0.378 and 0.165. Added resistance and hydrodynamic responses in head seas were measured in a captive setup. Some of the test cases were repeated in a free-sailing mode. Experiments provided validation data for numerical computational fluid dynamics (CFD) simulations, which were performed using a Reynolds-Averaged Navier–Stokes (RANS) solver, k-ω turbulence model, and a Volume of Fluid approach. Numerical results generally correlate well with experimental results. In addition to model-scale analysis, CFD simulations were also performed at full-scale to study scale effects.