Ship-ship interactions in calm water and waves. Part 1: Analysis of the experimental data

Abstract

Part 1 of this two-part paper presents detailed analysis of the previously conducted ship-ship experiments for Bob Hope and Bobo free to heave and pitch in deep calm water and waves (Van't Veer and Van Engelenburg, 2006). Interactions are quantified, recommendations for future experiments are provided, and the results are used as basis for selection of simulation conditions in Part 2. Calm water interactions include induced side forces and rolling and yawing moments on both ships. Effects of changing the configuration, decreasing the spacing, and increasing the speed are to intensify or diminish these induced effects, depending on the variable and the test conditions. In waves, the important effects include increased interactions in resonance region, sheltering of one ship by the other in oblique waves, and elevated amplitudes of forces and moments at high frequencies where the motion amplitudes are nearly zero. Effects of configuration, speed, and heading are studied both on trends with frequency and averaged over all frequencies, showing different effects depending on the test conditions. Part 2 provides validation studies for selected conditions, as well as further investigation of the physics through comparison with single-ship simulations and analysis of the global and local flow variables.