Numerical simulation of bow thruster induced near-bed flow next to quay wall

Master thesis (2021)

Authors

T.B.L. Haafkes Mechanical Engineering

Contributors

T.J.C. van Terwisga Ship Hydromechanics and Structures - Mechanical, Maritime and Materials Engineering (supervisor 1)
H.J. de Koning Gans Ship Hydromechanics and Structures - Mechanical, Maritime and Materials Engineering (supervisor 2)
T.S.D. O'Mahoney Deltares (supervisor 1)
A.J. van der Hout Rivers, Ports, Waterways and Dredging Engineering - CEG (supervisor 2)
Faculty
Mechanical Engineering
Copyright: © 2021 Thom Haafkes
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Published Date

21-05-2021

Language

English

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Faculty

Mechanical Engineering

Abstract

During berthing operations of ships, the horizontal thrusters cause a hydraulic load on the quay wall and bed. This could eventually lead to scour holes in the bed, which may affect the structural integrity of the quay wall. This thesis is about a numerical simulation of a bowthruster jet which is deflected by a quay wall and the focus of this study will be on the resulting bottom velocities. In 2019, field measurements were executed with an inland vessel and the measured bottom velocities were low compared to the design guidelines. The goal of this study is to simulate the field measurements in a numerical model to gather more knowledge about the flow field induced by bowthrusters next to quay walls. The obtained numerical results are compared to the field measurement and to the design guidelines of PIANC. As it turns out, the velocity sensors probably did not measure the maximum bottom velocity during the field measurements, since they are located slightly above the highest velocities at the bottom, as predicted by the numerical simulations. The maximum bottom velocities from the numerical simulation are similar to the expected near-bed bottom velocities by PIANC. However, there is room for improvement in these design guidelines, e.g., adjusting the efflux velocity for tunnel thrusters to account for the variation in cross-sectional area between propeller and tunnel exit.