Effect of tabs on the shear layer dynamics of a jet in cross-flow

Direct numerical simulations (DNS) of a jet in cross-flow (JICF) with triangular tab at two positions are performed jet-to-cross-flow velocity ratios $R = 2$ and $4$ Reynolds number 2000 based on the jet's bulk exit diameter. The DNS dynamic mode decomposition show sensitivity tab's effect upstream shear layer (USL) structure cross-section to $R$ , echoing experimental discoveries Harris et al. ( J. Fluid Mech. vol. 918, 2021). Furthermore, reveals that presence placed side nozzle significantly modifies USL through production streamwise vortices curl around spanwise vortex tubes originating from primary instability USL. This provides an explanation for improvement mixing has been associated tab. shows remarkable similarities ‘strain-oriented tubes’ observed disturbed plane layers by Lasheras & Choi 189, 1988, pp. 53–86). For both cases, is delayed, penetration reduced, flattened, although less pronounced higher ratios, where formation delayed. In contrast, 45 $^\circ$ position produces different effects compared At 4$ skewed away tertiary formed, as past studies round JICFs relatively high low numbers. ability produce controllable steady-state implications variety applications. asymmetric wake but much smaller, highlighting jets perturbations.