  Rotation modulates turbulence causing columnar structuring of a turbulent
flow in case of sufficiently strong rotation. This yields significant changes
in the flow characteristics and dispersion properties, which makes rotational
turbulence modulation particularly relevant in the context of atmospheric and
oceanic flows. Here we investigate the canonical flow of turbulence in a
periodic box, subjected to rotation about a fixed vertical axis. As point of
reference we consider direct numerical simulations of homogeneous isotropic
turbulence. Modulation due to rotation at various rotation rates (i.e.,
different Rossby numbers) is investigated. Special attention is paid to the
alteration of intermittency, which is measured in terms of changes in the
scaling of the structure functions. A reduction of intermittency quantified
with the longitudinal structure functions in the direction perpendicular to the
rotation axes will be presented. These numerical findings correspond well to
recent results obtained in experiments by Seiwert et al. (2008).
