NUMERICAL PREDICTION OF SOLITARY WAVE FORMATION OF A PLANING HULL IN SHALLOW WATER CHANNELS

This paper uses a CFD (Computational Fluid Dynamics) analysis to investigate the shallow water effects on prismatic planing hull. The turbulence flow around the hull was described by Reynolds Navier Stokes equations RANSE using the k-ɛ turbulence model. The free surface was modelled by the volume of fluid (VOF) method. The analysis was steady for all the range of speeds except those close to the critical speed range due to the propagation of the planing hull solitary waves at this range. In this study, the planing hull lift force, total resistance, and wave pattern for the range of subcritical speeds, critical speeds, and supercritical speeds have been calculated using CFD. The numerical results have been compared with experimental results. The pressure distribution on the planing hull and its wave pattern at critical speed in shallow water were compared with those in deep water

Numerical prediction of sheet cavitation on marine propellers using CFD simulation with transition-sensitive turbulence model

One of the big challenges, yet to be addressed, in the numerical simulation of cavitating flow on marine propellers is; the existence of laminar and turbulence transition flows over the propeller’s blades. The majority of previous studies employed turbulence models that were only appropriate for fully turbulent flows. These models mostly caused high discrepancies between numerical predictions and experimental measurements especially at low rotational speeds where, Reynolds number decreases and laminar and transient flows exist. The present paper proposes a complete and detailed procedure for the CFD simulation of cavitating flow on marine propellers using the ‘K-Kl-ω’ transition-sensitive model. Results are obtained using ‘ANSYS FLUENT 16’. The propeller under consideration is the ‘INSEAN E779A’ propeller model. The fully turbulent standard ‘k-ε’ model is also adopted for comparison. Obtained results, based on both turbulence models, are validated by comparison with experimental data available in the literature. Predictions based on the ‘K-Kl-ω’ transition-sensitive model are found to be in better agreement with experiments at lower rotational speeds i.e. at low Reynolds numbers. Keywords: CFD simulations, Marine propellers, Cavitation, Multi-phase flow, Turbulence models, Transition-sensitive model