PREDICTION OF VISCOUS SHIP ROLL DAMPING BY UNSTEADY NAVIER-STOKES TECHNIQUES

This paper describes a numerical technique for analyzing the viscous u nsteady flow around oscillating ship hulls. The technique is based on a general Reynolds-averaged Navier-Stokes (RANS) capability,: and is i ntended to generate viscous roll moment data for the incorporation of real-flow effects into potential flaw ship motions programs. The appro ach utilizes the finite analytic technique for discretizing the unstea dy RANS equations, and a variety of advanced turbulence models Sor clo sure. The calculations presented herein focus on viscous and vortical effects without free-surface, and utilize k-epsilon turbulence modelin g, Series variations are presented to study the effects of frequency, amplitude, Reynolds number, mid the presence of bilge keels, Moment co mponent breakdown studies are performed in each case to isolate the ef fects of viscosity vorticity, and potential flow pressures.