Detached Eddy Simulation of Free-Surface Flow Around a Submerged Submarine Fairwater

The effects of reducing submergence depth around a submerged submarine fairwater without its associated appendages is numerically studied using detached eddy simulation. The submerged body is modeled using the ghost-cell immersed boundary method, while the free-surface is accounted for by using a moving mesh. The numerical simulations are performed at a Reynolds number of 11 × 10⁶ for a submergence ratio in the range of 0.44–0.32 and for Froude numbers <1. This paper examines the effect of depth variation on the statistical and structural behavior of the flow around a fully submerged fairwater. The results include profiles of the time averaged velocity, turbulent intensities, turbulent kinetic energy spectra and budget. These have all shown that the major part of the turbulence is confined to the near wake region of the fairwater. Vortical structures are found to show no significant rise or interaction with the free-surface, while in the wake region, the results show that vorticity is present for over 50% of the total monitored period. Reducing the submergence depth is found to influence the tip vortex shedding. Additionally, time averaged forces, force variations, and shedding frequency are also examined. In all cases, the surface waves generated by the submerged fairwater are of a Kelvin kind.