Efficient Modelling of Harsh Environment Disturbances for DP and Autonomous Ships Simulations

Numerical modelling of the Arctic ocean dynamics with real-time simulation capability is useful for designing, developing, testing, and validating the performance of Dynamically Positioned (DP) and Autonomous ships/offshore platforms. Advanced simulation technology needs to be developed to predict the expected loads on these systems due to the complex interactions with environmental disturbances. This paper presents models of waves, currents, wind, and ice that comply with the real-time simulation requirements and adequately capture the dynamic characteristics of the most relevant physical processes. A 3D dispersive numerical model is deployed to predict the wave parameters to be utilized to compute the wave loads on a ship with known Response Amplitude Operators (RAO). A uniform current load is then incorporated in a superposition manner by using a combined wave-current field dispersion relation capable of expressing the wavenumber of an interactive wave-current field. The mean and the gust wind components are added to the resultant force components. A multiple regression-based ice model is used to predict the loads caused by an ice field characterized by varied ice thickness, concentration, floe size, drift speed and directions. The stationkeeping performance of a generic DP-controlled ship subjected to environmental disturbances is evaluated for a range of environmental conditions. The proposed models can help design, develop, and evaluate dynamic positioning and autonomous ship controllers’ performance. Another application may be developing a realistic simulation environment to train conventional, DP-controlled and autonomous ship operators.