_:b670468098 "https://en.wikipedia.org/wiki/Boundary_layer" . _:b670468098 . _:b670468098 . _:b670468098 "A boundary layer is a layer of fluid in the immediate vicinity of a bounding surface where the effects of viscosity are significant enough to distort the surrounding non-viscous flow." . _:b670468098 . _:b670468098 .