Tug Bollard Pull Test powered with a Voith Schneider Propeller by Computational Fluid Dynamics (CFD)

Abstract

In the design phase of the dimensioning process of a ship, it is difficult to be precise about the thrust results in the propeller studies. The exact thrust that the propeller will produce and the thrust that will be lost toe to the viscous forces is, nowadays, known only when the vessel is already built and the test of thrust of the boats, called bollard pull test, is performed. Thanks to the informatics development, the computational fluid dynamics is bringing betler results every day. The importance of numerical simulations in various fields of application is by now widely accepted. There are in particular relevant cases where experiments are too costly, too dangerous or even impossible when the process to be simulated is not even observable in experiments. Therefore computational fluid dynamics (CFD) simulations it is an economic and reliable way to determinate the boat capacities before its co nstructio n. This study is focused in simulating the bollard pull test of a concrete tug, check the results and from there analyse the zone requirements from the Classification Societies. These Societies made studies to determinate the requirements of the zone for the bollard pull test performance of boats with regular propellers (screw propeller), but it is not the only kind of existent propellers. In this study many simulations of a tug with a Voith Schneider Propeller will be run and analysed. The effect that makes the characteristics of the zone where the test have to be performed will be studied. Also the requirements of the Classifications Societies will be simulated for this tug with the VSP. After analysing and comparing all the simulations results, possible requirements for the bollard pull test zone for boats with a VSP will be suggested.