Influence of turbulence closure models on the vortical flow field around a submarine body undergoing steady drift

Manoeuvring underwater vehicles experience complex three dimensional flow. Features include stagnation and boundary layer separation along a convex surface. The resulting free vortex sheet rolls up to form a pair of streamwise body vortices. The track and strength of the body vortex pair results in a nonlinear increase in lift with as body incidence increases. Consequently, accurate capture of the body vortex pair is essential if the flow field around a manoeuvring submarine and the resulting hydrodynamic loading is to be correctly found. This work highlights the importance of both grid convergence and turbulence closure models on the strength and path of the crossflow induced body vortices experienced by the DOR submarine model at an incidence angle of 15◦. Five turbulence closure models are considered; Spalart-Allmaras, k − ε, k − ω, Shear Stress Transport and the SSG Reynolds stress model. The SSG Reynolds stress model shows potential improvements in predicting both the path and strength of the body vortex over standard one and two equation turbulence closure models based on an eddy viscosity approach.