Multiscale analysis of the Reynolds stress, dissipation, and subgrid-scale tensor in turbulent bubbly channel flows: Characterization of anisotropy and modeling implications

A direct numerical simulation database of bubbly channel flows at friction Reynolds number 180 and with three different global void fractions has been used to perform a multiscale analysis the anisotropy stress tensor, dissipation subgrid-scale (SGS) tensor in order characterize turbulence for wide range scales down smallest structures occurring flow. Based on hypothesis Kolmogorov, non-linear turbulent energy transfer is expected result loss directional information such that, sufficiently high number, small-scale be isotropic universal. The present reveals that presence bubbles increases flow which persists motion, even SGS tensor. This implications complete landscape modeling approaches ranging from large eddy simulation, over hybrid averaged Navier–Stokes based modeling.