Experimental Evaluation of a Dynamic Positioning Thruster Prohibited Operating Zone Using Stereoscopic Particle Image Velocimetry (SPIV)

The knowledge of the effects of the wakes from Dynamic Positioning (DP) thrusters and the practical need to describe and predict their impact is fundamental in the assessment of design loading on slipstream-submerged structures (moorings, risers, and equipment) associated with offshore floating systems. In particular, with the increasing importance and application of DP thrusters in the offshore industry, the designer as well as the operator must have more information about thruster-structures interaction effects and the safest location of DP thrusters regarding to any submerged structures. This paper contributes at this knowledge by experimentally evaluating of a DP thruster model far wake induced load. This is by evaluating the DP thruster wake thrust and force loading distribution and propagation, when operating with and without a nozzle, at high loading conditions (J = 0 and J = 0.4) and up to 15 diameters downstream of the model. Experiments were performed using a Stereoscopic Particle Image Velocimetry (SPIV) at the Italian Ship Model Basin (INSEAN) large cavitation tunnel. This paper evaluates the safest location of DP thruster when operating with and without a nozzle.