This paper presents recent advances of the SWENSE (Spectral Wave Explicit Navier-Stokes Equations) approach, a method for simulating fully nonlinear wave-body interactions including viscous effects. Potential flow theory is used to compute the incident waves while viscous effects are taken into account by using a Reynolds Averaged Navier- Stokes Equations (RANSE) solver to obtain the diffracted field in the full domain. Arbitrary incident wave systems can be described, including regular, irregular waves, multidirectional waves and focused wave events. The model may be fixed or moving with arbitrary speed and 6 degrees of freedom motion. This paper is devoted to the validation of the SWENSE method in irregular head waves, in the case of an extensively long 2 DoF simulation. Results of the present approach compare favorably with experimental data.
Performance and seakeeping predictions are usually carried out in towing tank. However, in ship hydrodynamics, Computational Fluid Dynamics (CFD) is more and more used as a practical design tool. Main advantages of CFD are cost and time reduction as well as easier access to detailed flow field information. The complexity of simulating the behaviour of a ship in seaways was historically overcome by separating the problem in many simpler analysis: resistance, propulsion, maneuvering and seakeeping. Although these aspects are strongly coupled, CFD tends to simulate each of these phenomena separately using adapted theories :
Resistance and propulsion analysis are now often addressed using viscous flow solvers based on the solution of RANS Equations, because viscosity or flow separation effects play an important role in the physics of those phenomena.
Maneuvering and seakeeping problems are still currently solved by potential flow theory which is less time consuming and enables an accurate and efficient account of wave propagation phenomena.