Title: Turbulent shear layers in confining channels,
Abstract: We present a simple model for the development of shear layers between
parallel flows in confining channels. Such flows are important across a wide
range of topics from diffusers, nozzles and ducts to urban air flow and
geophysical fluid dynamics. The model approximates the flow in the shear layer
as a linear profile separating uniform-velocity streams. Both the channel
geometry and wall drag affect the development of the flow. The model shows good
agreement with both particle-image-velocimetry experiments and computational
turbulence modelling. The low computational cost of the model allows it to be
used for design purposes, which we demonstrate by investigating optimal
pressure recovery in diffusers with non-uniform inflow.