Flow features of confined swirling jets

Abstract

Assessment of LES models of confined coaxial swirling jets is the aim of this paper. Despitethe simple geometrical set- up of the benchmark, the flow pattern shows complex aerodynamicbehavior. The case considers two coaxial jets: one axial and another annular swirling jet. Theexpansion when entering the chamber will produce the Outer Recirculation Zone (ORZ). Ifswirl number is large enough, an Inner Recirculation Zone (IRZ) is formed. The regionbetween both recirculation zones with high shear is where mixture occurs. Post - process inspace and frequency domain supplies useful information of this benchmark. Kernel cores areidentified based on the lambda2 parameter. The mesh must be fine enough to capture theinertial regime of the turbulent energy spectrum. Proper Orthogonal Decomposition letidentify main flow structures. To sum up, LES models provide more information thanconventional RANS models and it is a step forward in any research team to gain an insight ofany transitional or fully turbulent process.