Resolving the lift and drag forces on a body or obstacle and its associated disturbance of the flow requires the use of a resolution much smaller than the scales of the body. This is particularly the case if the boundary layer forming on the parts of the body exposed to the flow needs to be resolved. (This ultimately becomes detached and contributes a free shear layer to the disturbance downstream.)
- If there are gradients in the pressure-adjusted density within the ambient fluid, the disturbance may extend far from the body (many times its longest length scale).
- Full simulation involves coupling one of the mesoscale models in use in the Group to a microscale model employing computational fluid dynamics (CFD).
- Where turbulence arises in the ambient or disturbed flow, changes in the forcing on time scales somewhat greater than that of the energy-containing eddies may be simulated through Reynolds averaging.
- To model unsteady effects such as eddy shedding and jet or wake meandering – and establish the contribution of these effects to Reynolds-averaged characteristics – requires use of large-eddy simulation (LES; or a hybrid scheme such as detached-eddy simulation).
- Applications that have been simulated here include fixed and floating wind turbines in offshore wind farms; fish farms; and the outflux of supersaturated CO2 from a rupture at the seabed in carbon-capture-and-storage (CCS) infrastructure.
- Both proprietary (Star-CCM) and open-source (OpenFOAM) CFD software have been used.