ABSTRACT
Confined incompressible turbulent swirling flows exhibiting vortex breakdown have been computationally investigated. Transient Reynolds averaged numerical simulations (T-RANS) have been performed employing a differential Reynolds stress model (RSM) to address turbulence. It has been shown that much better agreement with experimental data can be achieved utilizing this approach in comparison to a steady-state procedure. This reveals the importance of the coherent transient motion in combination with the non-isotropic turbulence structure in swirling flows. The predictability of the vortex core transition and the influence of downstream conditions on the upstream flow, depending on whether the flow is sub- or super-critical, has also been investigated.