Verification and validation of hard-chine hull performance in calm water: Effects of numerical setups and hull configurations

Abstract

Recent studies show that the numerical estimations of resistance of planing hulls differ from experimental results by 10 %–20 %, mainly due to the absence of a towing force in the conventional 2DOF numerical model and the geometric differences between the 3D model in the simulations and the physical model in experiments.

This study investigates the effect of a towing force on the performance of a conventional 2DOF setup with overset grid, and compares it with a 3DOF setup, typically used for manoeuvring simulations. Additionally, different wall treatment approaches (y+ < 5 and y+ > 30) are compared. Verification and validation analysis is conducted for the bare hull and the validated numerical models are used to compare hulls equipped with spray rails, chine strips and V-shaped spray interceptors.

Models directly solving the viscous sub-layer (y+ < 5) were invalidated since their comparison errors in running position and resistance exceeded the validation uncertainty. Conversely, numerical models employing wall functions for wall treatment (y+ > 30) accurately predicted both the running position and the resistance of the bare hull within the validation uncertainty. Introducing a towing force in the 2DOF model improved the prediction of the running position, while the 3DOF setup demonstrated better overall accuracy.