The spatio-temporal dynamics of momentum-carrying and vortical structures in transitional and fully-developed wall-bounded turbulence

The late stages of transition are characterized by the breakdown and coalescence of multiple structures. During this breakdown, these structures visually appear less complex and more ordered than their fully turbulent counterparts. However, in regions of intense momentum transfer, the single-point (Park et al., 2012; Sayadi et al., 2013) and geometrical metrics (Elnahhas et al., 2022) of these transitional structures are statistically similar to their fully turbulent counterparts. In this work we analyze the dynamical properties of these transitional structures. Utilizing a generalized multi-type spatio-temporal tracking algorithm (Lozano-Duran & Jimenez, 2014; Elnahhas et al., 2023), two sets of structures, namely momentum transfer and three-dimensional vortical structures, are tracked simultaneously in the transitional and fully-developed regions of an H-type transitional boundary layer. In both regions, we analyze the statistical properties throughout the lifetimes of the structures and the interactions between the two sets. While the geometric properties adjust to the turbulent scaling laws immediately upon breakdown, the dynamical properties appear to take a longer downstream distance to forget the transition process and adjust to the turbulent scaling laws.