Turning circle tests with system-based simulations in irregular waves including wave drift and propeller side forces

Abstract

Controlled motion in seas require mathematical modeling of ship motions under external disturbances. Waves are one of the most influential factors that undermine ship control. In this study, we investigate the maneuvering ability of the benchmark Japan Bulk Carrier (JBC) in calm water and in waves. Turning circle tests are conducted via system-based analysis and direct CFD method in calm water condition. Comparison of system-based analysis with experiments and direct CFD method have shown to be satisfactory. After validation of the mathematical model, empirical relations are used to include the ship drift in irregular wave conditions. Two different cases are considered. The first one is with constant significant wave height and changing wave angles. The second case is with constant wave angle but different significant wave height. The ship drift was observed to be in the direction of wave propagation, growing larger with increasing wave height. The maneuvering indices with changing wave directions were graphed and it revealed the maneuvering capability of JBC under the disturbance of waves.