High Reynolds number wall-bounded turbulence and a proposal for a new eddy-based model

We propose a model for turbulent wall-bounded flows based on new understanding of the turbulent structure. Specifically, we identify three basic eddy motions: (1) the Large-Scale Motions (LSMs) which are related to the vortex packets defined by Head and Bandyopadhyay (1981) and Adrian et al. (2000); (2) the Very Large-Scale Motions (VLSMs) interpreted by Liu et al. (2001) and Balakumar and Adrian (2007) in terms of a concatenation of the outer layer bulges and by Monty et al. (2007) in terms of the meandering "superstructures" observed in pipe, channel and boundary layers; and (3) the streaks associated with longitudinal vortex-like structures in the near-wall region, as identified by Kline et al. (1967). The new model maps the attributes of each eddy type in physical space to wavenumber space. Experimental data are then used to determine the scaling behavior of the three basic eddy motions in wavenumber space, and the scaling behavior of the Reynolds stress behavior is recovered b! y integrating over all wavenumbers.