Numerical prediction of free-surface wave induced separation on a 3D floating body

Abstract

In this research, the effects of free-surface wave and wave induced separation on a 3D surface piercing floating body has been studied. The simulation has been performed using a commercial Computational Fluid Dynamics (CFD) code ANSYS Fluent based on Finite Volume Method (FVM). The predicted results for several Froude numbers (Fr = 0.19, 0.37, and 0.55) have been studied for surface piercing body with NACA 0024 airfoil section and validated with both the experimental data and the previous numerical result. The thickness effects on the wave-induced separation have been evaluated for surface piercing bodies with NACA 0012 and NACA 0018 airfoil sections, whereas surface piercing bodies with cylindrical, elliptical and rectangular cross-sections have been used to evaluate the shape effects. It has been found that the wave height, wave steepness, and distortion in the separation region changes abruptly with the change in Froude number. The wave patterns are dependent on Froude number rather than thickness or shape of the floating body at higher Froude number but the thickness or shape effects become dominant at lower Froude number. The thickness or shape effects are noticeable in the bow wave peak, extent of the free – surface, at the wake region, and also in the separation region. Free-surface elevations and other flow characteristics have also been studied for the surface piercing bodies with NACA 0012, NACA 0018, NACA 0024, cylindrical, elliptical, and rectangular sections.