ABSTRACT

A 3-D model for hydrodynamic performance and Stokes waves propagation on the free surface is established using the Navier-Stokes equations and Stokes wave theory. The realizable k – ε turbulence model has been implemented to capture turbulent flow around the ship hull. The tracking of the interface between the air and water is accomplished by the method of VOF(Volume Of Fraction). The motion of the ship hull is simulated using 6 degrees of freedom(6 DOF). Because the heave and pitch is the most attractive parameter, both of them are addressed specially considering the calculating cost and efficiency. Simulated water surface profile and Z-velocity distribution agree well with the theoretical value, indicating that this model has a great ability in simulating wave-current-structure interaction. The propagation of Stokes wave traveling with a ship hull is also numerically investigated by this model. Then the character of the phase fraction of the free surface and the flow profiles are studied. The interface between the water and air on the ship hull's boundary is also compared with the original surface under the wave's action.

INTRODUCTION

To analyze the performance of hydrodynamics and waves around a ship hull on the free surface is one of the important subjects in basic hydrodynamics and attracted by a number of researchers. When the ship is sailing on the free surface, especially with wind and waves, free surface effect should be considered including evaluations of free surface profile, pressure and velocity distribution, hydrodynamics and wave performance, and the ship's response as well. This paper is concerned with the two phase flow and wave generation due to the flow around a ship hull moving on the free surface.

There are many correlative studies on the interactions between the water waves and structures with different types, including the fully submerged structures (Clement and Mas, 1995; Boo, 2002; Koo et al., 2004; Vengatesan et al., 2006, etc.), vertical cylinders/plates (Li and Lin, 2001; Pradip and Sukamal, 2006; Wang and Wu, 2010, etc.), the surface-piercing bodies (Nojiri and Murayama, 1975; Tanizawa and Minami, 1998; Fang and Chen, 2001; Koo and Kim, 2007a, 2007b; Li and Lin, 2010, etc.) and other types of structures. Some of the other researchers investigated the interaction problem using numerical wave tank. In Boo's work(2002), a time-domain numerical scheme was used to simulate the linear irregular waves in numerical tank and the linear and nonlinear irregular wave diffraction forces acting on a submerged structure was predicted. Koo and Kim(2007a) studied the wave body interactions for stationary floating single and double bodies using a potential-theory-based fully nonlinear 2-D numerical wave tank. Li and Lin(2010) investigated the fully nonlinear wave-body interactions for a surface-piercing body in finite water depth with flat/slop bottom topography. A 2-D numerical regular wave tank was built, which mainly based on the spatially averaged Navier-Stokes equations and

This content is only available via PDF.
You can access this article if you purchase or spend a download.