  Low Reynolds number turbulence in wall-bounded shear flows \emph{en route} to
laminar flow takes the form of oblique, spatially-intermittent turbulent
structures. In plane Couette flow, these emerge from uniform turbulence via a
spatiotemporal intermittent process in which localised quasi-laminar gaps
randomly nucleate and disappear. For slightly lower Reynolds numbers, spatially
periodic and approximately stationary turbulent-laminar patterns predominate.
The statistics of quasi-laminar regions, including the distributions of space
and time scales and their Reynolds number dependence, are analysed. A smooth,
but marked transition is observed between uniform turbulence and flow with
intermittent quasi-laminar gaps, whereas the transition from gaps to regular
patterns is more gradual. Wavelength selection in these patterns is analysed
via numerical simulations in oblique domains of various sizes. Via lifetime
measurements in minimal domains, and a wavelet-based analysis of wavelength
predominance in a large domain, we quantify the existence and non-linear
stability of a pattern as a function of wavelength and Reynolds number. We
report that the preferred wavelength maximises the energy and dissipation of
the large-scale flow along laminar-turbulent interfaces. This optimal behaviour
is primarily due to the advective nature of the large-scale flow, with
turbulent fluctuations playing only a secondary role.

Fluid Dynamics;Pattern Formation and Solitons