Global modes and large-scale structures in an Ekman boundary layer

Motivated by the dynamics of the atmospheric boundary layer, the present work examines the influence of Coriolis acceleration on wall-bounded turbulence. The large-scale structures of an Ekman boundary layer are compared to those of a channel. The distribution of energy across scales is studied by looking into the spectra of the velocity fluctuations. Linear stability analysis reveals the existence of an unstable range of wavenumbers which sustain the turbulence and lead to transverse "roll" structures observed in instantaneous snapshots of the flow.