Abstract
In the Deep-Sea Mining, the seafloor mining tool is connected to the subsea slurry pump by a piece of flexible pipe named jumper. The jumper’s shape is similar to a steep-wave flexible riser. Compared to a flexible riser, the jumper is a reinforced hose and has a shorter length. Numerous studies shed light on the dynamic behavior of flexible riser; however, all studies were carried out by the way of numerical analysis. We carried out, in the Deep-Sea Basin, an experiment using 1/5 reduced scale model of the jumper. Unhappily, the model’s bending stiffness had to be distorted. During the experiment, an oscillator generated harmonic motion on the top end of the model and a centrifugal pump circulated water throughout the model. In addition, we installed load cells on the top and bottom ends of the model. Our Basin is equipped with a visual measurement system. Thus, we measured the displacement of targets attached to the model. The initial results show that axial tension amplitude increases with the frequency of the top end oscillation. This response is due to the drag force on the lower bend increases with the frequency of top motion. We also could observe that the internal flow may increase the vertical motion amplitude. The jumper’s motion generates an oscillation on the internal differential pressure between both ends and the flow velocity. The differential pressure amplitude increases with the top oscillation frequency, but it is proportional to the top end oscillation amplitude. We will use these experimental results to validate our numerical models. Further, it is important to understand the internal flow effects to design the actual pump used to convey the slurry through the jumper.
