Modeling of swirling flows with coherent structures using the unsteady Reynolds stress transport model

Swirling flows are investigated using an unsteady model based on the Reynolds stress transport equations. Swirling flows with vortex core precession are considered, namely, the swirling flow behind an abrupt expansion and the swirling flow in a burner with an annular fuel inlet. The method under consideration is shown to well reproduce the recirculation flow formed as a result of the vortex core precession, with respect to both mean and fluctuation parameters. At the same time, the calculations in accordance with the unsteady model prolong the central recirculation zone. It is established that the contributions made by the resolvable and modeled components of the Reynolds stress tensor to the turbulent transport are comparable.