Modelling the formation and dispersal of streamwise vortices in turbulent flow

Abstract In many practical circumstances in aeronautical engineering and in related industries, flows arise where concentrated streamwise vorticity is embedded within a turbulent shear flow. The juxtaposition of these features makes such flows particularly challenging to compute using CFD methods. In particular, one may be forced to abandon strategies for modelling the turbulent stresses that prove adequate in two dimensional shear flows (i.e. in flows where the vorticity vector is orthogonal to the mean velocity). The paper reviews developments in modelling turbulent stresses from their transport equations (rather than by appeal to an eddy viscosity hypothesis) and demonstrates, by way of a range of examples, the capabilities of this approach for handling flows with concentrated streamwise vorticity.