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.


    Access

    Download


    Export, share and cite



    Title :

    Performance of azimuth and bow thrusters during ship maneuvers


    Contributors:
    Wang, Keqi (author) / TUHH Universitätsbibliothek (host institution)

    Publication date :

    2025



    Type of media :

    Miscellaneous


    Type of material :

    Electronic Resource


    Language :

    English



    Classification :

    DDC:    004 / 629 / 620




    A Spin on Azimuth Thrusters!

    Novotny, A. / ABR | British Library Conference Proceedings | 2004



    Azimuth Thrusters in Ice-Going Tugs

    Jarvinen, R. / ABR Company Limited | British Library Conference Proceedings | 2006



    AZIMUTH THRUSTERS FOR VESSEL WITH NO EXTERNAL BLADES

    HAN KWANG HEE | European Patent Office | 2019

    Free access