Effect of swirl on linear formation of streaks in jets

Streaks in turbulent jets are a recent finding, dominating kinetic energy at low frequencies. It is an experimental result that is interesting in and of itself as one of the few coherent structures observed in this setting. Similar structures are known to be present and play a critical role in wall-bounded transition to turbulence. We propose to investigate the linear dynamics of streak generation in swirling jets. We compute a turbulent baseflow from the RANS equations at high Reynolds number, then leverage resolvent and modal analysis to study linear amplification mechanisms of the turbulent jet. We study a 2D azimuthally decomposed geometry with a 3D incompressible flow, and look at the effect of swirl on the linear mechanisms that give rise to growth of streaks. We include a nozzle in the calculation and use an eddy viscosity obtained from our RANS calculation.