The layers meet in the middle and merge, and the flow reaches an asymptotic state called fully-developed flow (figure 8). Boundary layers in an external flow, such as the airfoil shown in figure 9, ...

The Boundary ... developed boundary layer over 25 cm thick (Re τ ≈ 10,000). Even thicker boundary layers are achievable using custom-designed surface roughness elements and spires tailored to the wind ...