Numerical Study of Green Water on a Tumblehome Vessel in Strong Nonlinear Regular Waves

Abstract

Owing to the large amplitude and nonlinearity of extreme sea waves, sailing ships exhibit obvious large-amplitude motion and green water. For a tumblehome vessel, a low-tumblehome freeboard and wave-piercing bow make green water more likely. To study the green water of a wave-facing sailing tumblehome vessel in strong nonlinear regular waves, the computational fluid dynamics software STAR-CCM+ was used. The Reynolds-averaged Navier—Stokes method was used for the numerical simulation, and the k-epsilon model was adopted to deal with viscous turbulence. The volume of the fluid method was used to capture the free surface, and overset grids were utilized to simulate the large-amplitude ship motion. This study delves into the influence of wave height on the ship motion response and a tumblehome vessel green water under a large wave steepness (0.033 ⩽; H/λ ⩽ 0.067) at Fr = 0.22. In addition, the dynamic process of green water and the “wave run-up” phenomenon were evaluated. The results suggest that when the wavelength is equal to the ship length and the wave steepness increases to 0.056, the increase in the water height on the deck is obvious. However, the wave height had little effect on the green water duration. The wave steepness and “backwater” have a great impact on the value and number of the peak of the water height on the deck. When the wave steepness exceeded 0.056, the water climbed up, and the plunging-type water body was formed at the top of the wave baffle, resulting in a large water area on the deck.

Keywords

Tumblehome vessel / Green water / Impact loads / Wave run-up / Strong nonlinear regular waves

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