Validation of the CFD code Flow-3D for the free surface flow around the ships’ hulls

This paper describes the Computational Fluid Dynamics (CFD) calculations that were completed to model the free surface flow around the ships’ hulls. Published experimental data for the DTRC 5415 combatant model is commonly used for validation of numerical codes. Simulations were performed using the software Flow-3D, a Reynold’s Averaged Navier-Stokes (RANS) solver with structured orthogonal mesh. The verification was based on the examination of the flow around the hull for range of speeds and by comparison of the results for resistance obtained by CFD simulations and by experiments. Additional analysis has been conducted to investigate mesh sensitivity and the implementation of different advection schemes. The second order advection scheme with monotonicity preserving was optimal for the qualitative analysis of the problem under consideration. This study shows that CFD code Flow-3D has a limited capability to resolve the physics of the flow around the hull. The shape of the free surface and wave distributions around the hull corresponds approximately to the experimental observations. For quantitative analysis of ship total resistance, Flow-3D shows a lack of accuracy. It appears that the code does not have the capability to properly resolve boundary layer on the hull and properly predict frictional resistance. It can be improved by using only dynamic pressure results and by using some established empirical/experimental approach for estimating frictional resistance. The multi-block grids and the different turbulent models are being used to obtain valid numerical results that are crucial for making sound design decision