Options
Performance of azimuth and bow thrusters during ship maneuvers
Citation Link: https://doi.org/10.15480/882.15017
Publikationstyp
Doctoral Thesis
Date Issued
2025
Sprache
English
Author(s)
Advisor
Referee
Title Granting Institution
Hamburg University of Technology
Place of Title Granting Institution
Hamburg
Examination Date
2025-03-03
Institute
TORE-DOI
Citation
Technische Universität Hamburg (2025)
Active maneuvering devices improve the maneuverability of a vessel during departure and arrival, reducing the need for tug assistance. However, their operation in significant oblique flow conditions leads to complex flow behaviors, posing challenges in predicting the ship's response within the port environment.
This thesis develops an advanced maneuvering model that accounts for asymmetric flow interactions between the hull and maneuvering devices. An offshore supply vessel equipped with two stern azimuth thrusters and one bow thruster serves as the application case. The hydrodynamic performance of the vessel is evaluated using Reynolds-Averaged
Navier-Stokes equations (RANS) simulations.
Azimuth thrusters, being directly exposed to external flow, are highly sensitive to oblique inflow conditions. Under such conditions, the deformed propeller slipstream can result in the generation of thrust in excess of that observed under bollard pull conditions. This study identifies critical operating ranges to mitigate propulsion system failure through a systematic analysis of azimuth angles (from 0° bis +-180°), azimuth speeds, and ship speeds. The results of numerical simulation also support the development of an Artificial Neural Network (ANN) model for fast predicting the performance of thruster.
In contrast, the bow tunnel propeller is shielded from external flow. As a result, the oblique flow may not have a significant effect on the performance of the propeller. However, the effects of the slipstream-hull interaction are taken into account. To evaluate these interactions, static simulations are performed on a vessel equipped with a single bow thruster at varying ship speeds and inflow angles.
The transient effects of the slipstream are further analyzed by numerical Planar Motion Mechanism (PMM) tests. These tests not only capture transient phenomena, but also determine hydrodynamic derivatives which are subsequently integrated into the maneuvering model. To fully extract the interaction effects, the PMM tests are performed separately for the ship with and without tunnel thruster.
Finally, a maneuvering model is developed for ships equipped with two azimuth thrusters and one bow thruster. Using this model, turning circle simulations under various azimuth speeds, azimuth angles, and wake-field conditions demonstrate its effectiveness in predicting the ship's maneuvering performance.
This thesis develops an advanced maneuvering model that accounts for asymmetric flow interactions between the hull and maneuvering devices. An offshore supply vessel equipped with two stern azimuth thrusters and one bow thruster serves as the application case. The hydrodynamic performance of the vessel is evaluated using Reynolds-Averaged
Navier-Stokes equations (RANS) simulations.
Azimuth thrusters, being directly exposed to external flow, are highly sensitive to oblique inflow conditions. Under such conditions, the deformed propeller slipstream can result in the generation of thrust in excess of that observed under bollard pull conditions. This study identifies critical operating ranges to mitigate propulsion system failure through a systematic analysis of azimuth angles (from 0° bis +-180°), azimuth speeds, and ship speeds. The results of numerical simulation also support the development of an Artificial Neural Network (ANN) model for fast predicting the performance of thruster.
In contrast, the bow tunnel propeller is shielded from external flow. As a result, the oblique flow may not have a significant effect on the performance of the propeller. However, the effects of the slipstream-hull interaction are taken into account. To evaluate these interactions, static simulations are performed on a vessel equipped with a single bow thruster at varying ship speeds and inflow angles.
The transient effects of the slipstream are further analyzed by numerical Planar Motion Mechanism (PMM) tests. These tests not only capture transient phenomena, but also determine hydrodynamic derivatives which are subsequently integrated into the maneuvering model. To fully extract the interaction effects, the PMM tests are performed separately for the ship with and without tunnel thruster.
Finally, a maneuvering model is developed for ships equipped with two azimuth thrusters and one bow thruster. Using this model, turning circle simulations under various azimuth speeds, azimuth angles, and wake-field conditions demonstrate its effectiveness in predicting the ship's maneuvering performance.
Subjects
Maneuvering Model
Active Maneuvering Devices
Computational Fluid Dynamics
Artificial Neural Network
DDC Class
620: Engineering
629.89: Computer-Controlled Guidance
004: Computer Sciences
Loading...
Name
dissertation_keqi_wang_2025.pdf
Size
20.37 MB
Format
Adobe PDF