Lagrangian acceleration statistics in a fully developed turbulent channel
flow at Reτ​=1440 are investigated, based on tracer particle tracking in
experiments and direct numerical simulations. The evolution with wall distance
of the Lagrangian velocity and acceleration time scales is analyzed. Dependency
between acceleration components in the near-wall region is described using
cross-correlations and joint probability density functions. The strong
streamwise coherent vortices typical of wall-bounded turbulent flows are shown
to have a significant impact on the dynamics. This results in a strong
anisotropy at small scales in the near-wall region that remains present in most
of the channel. Such statistical properties may be used as constraints in
building advanced Lagrangian stochastic models to predict the dispersion and
mixing of chemical components for combustion or environmental studies.Comment: accepted for publication in Physical Review Fluid