Coupling model for real-time simulation of sailing ship motion under the influence of irregular waves and wind

The development of the interactive models for coupled dynamics of floating bodies in changing environments and wind-wave-body interactions is of paramount importance. This study presents a computationally cost-effective approach that implements the simplified but physically based sub-models combined into a single system. A realistic geometric model of the complex-shaped sailing ship, which is rigged with the adjustable sails and steered by the rudder, is selected as the object of numerical research. The irregular wind waves are simulated using in situ records of sea surface, probability description, and inverse fast Fourier transform. The complicated geometries of a floating object and arbitrary overwater obstacles, as well as changeable sea surface are represented as high-resolution triangular meshes. A six-degrees-of-freedom motion model for immersed rigid body is also integrated. A technique for the computation of wind loads on arbitrary-shaped adjustable sails, ship's hull, masts, and superstructures is proposed. The ship-generated waves that propagate and reflect at arbitrary obstacles are modelled using the linearized wave theory in conjunction with the two-dimensional convolution and masking operations, which are applied to a wave height field. A combination of the above approaches allows real-time conjugate modelling of the dynamics of a ship exposed to wind and irregular waves. Comparison between the real sailing ship and the virtual one is performed using an experimental polar diagram in terms of speed characteristics.