RANS Prediction of Wave-Induced Ship Motions, and Steady Wave Forces and Moments in Regular Waves

The wave-induced motions, and steady wave forces and moments for the oil tanker KVLCC2 in regular head and oblique waves are numerically predicted by using the expanded RANS solver based on OpenFOAM. New modules of wave boundary condition are programed into OpenFOAM for this purpose. In the present consideration, the steady wave forces and moments include not only the contribution of hydrodynamic effects but also the contribution of the inertial effects due to wave-induced ship motions. The computed results show that the contribution of the inertial effects due to heave and pitch in head waves is non-negligible when wave-induced motions are of large amplitude, for example, in long waves. The influence of wave amplitude on added resistance in head waves is also analyzed. The dimensionless added resistance becomes smaller with the increasing wave amplitude, indicating that added resistance is not proportional to the square of wave amplitude. However, wave amplitude seems not to affect the heave and pitch RAOs significantly. The steady wave surge force, sway force and yaw moment for the KVLCC2 with zero speed in oblique waves are computed as well. The present RANS results are compared with available experimental data, and very good agreements are found between them.

Special features of short-duration processes in condensed media

The problem of the short-duration processes is considered on the base of the nonlocal theory of non-equilibrium transport, taking into account inertial effects. The system temporal evolution out of equilibrium connected to the dynamic structure transition described by the Speed-Gradient principle (SG-principle or SGP) developed in control theory and cybernetic physics. In the manuscript, we show that retardation of the system response to the short-duration loading due to inertial effects influences on the system evolution and can change its direction. The response to the shock loading of condensed matter is compared to quasi-stationary loading in a wide range of conditions. The short duration loading can lead the system into the structure unstable state and even give rise to self-organization of turbulent structures in the medium. The use of SGP for the modelling of such processes opens new possibilities to control them.