A study of ship wake detection in the ocean

The turbulent structure of ship wake and ocean upper layer is presented in this study. The physical mechanism of a ship wake in the ocean is a result of the turbulence generated by a self-propelled ship. To formulate the ship wake problem, the shear-free model and two-dimensional turbulent diffusion in the cross-section of the wake have been applied, and self-modeling and Kolmogorov's hypothesis are used for the purpose of closure. The results of the calculation show how the size of the wake, turbulent kinetic energy and dissipation rate in the wake field depend on the speed and the dimension of the ship. The turbulence of the environmental ocean upper layer has been formulated by the assumption of horizontally uniform hydrodynamic field and k -- epsilon group model assuming the existence of surface waves and their breaking. The result shows that the turbulent kinetic energy and dissipation rate of turbulence in the ocean upper layer have power laws in decaying with depth. The combination of the ship wake and the upper layer turbulence gives the detection range on the ocean surface and the delectability in depth of the ship wake in terms of ship parameters and the wind speed.