Computational Analysis of the Performance of a Peripheral Thruster in Terms of Thrust Reduction and Unsteady Propeller Blade Loads at Non-zero Ship Speeds

The analysis presented in this article focuses on two aspects of the performance of a peripheral thruster, namely the reduction in thrust and increase in unsteady propeller blade loads with increasing ship speed. The peripheral thruster is an alternative design for the side thruster for a ship that consists of two separate devices mounted on two sides of the hull, with retractable ducted propellers, as opposed to a standard side thruster design, which uses a tunnel across the hull structure and a single propeller. The peripheral thruster was developed as an alternative solution to enable safe manoeuvring of floating units in which standard tunnel thrusters cannot be used, for example because the hull shape does not allow for the installation of the tunnel. Previous scale model tests have confirmed the efficiency of the peripheral thruster under bollard pull conditions. This research explores other important aspects of the operation of the thruster, i.e. how the thrust changes with increasing ship speed, how the unsteady propeller loads behave at non-zero speed, and how the peripheral thruster compares to a standard tunnel thruster in terms of these features. Computational work was carried out using the STAR-CCM+ solver.