 Planar turbulent mixing layer

A planar turbulent mixing layer develops between two parallel streams of different mean velocities. Their shear flow generates turbulence that transports streamwise linear momentum across the interface. A thin-layer eddy viscosity model with ${\nu }_T=C\Delta U\delta (x)$ has thickness proportional to downstream distance. For $\Delta U/U_c\ll 1$, its leading mean velocity transition is an error function.