Flat-plate boundary layer receptivity to a steady free-stream vortex disturbance

A single trailing vortex developed behind a micro-wing immersed in a free stream was used to study the vortex receptivity of the boundary layer on a flat plate. As a result of the interaction, in the boundary layer there develop longitudinal-velocity disturbances which grow almost linearly in the longitudinal coordinate. The parameters of the excited steady disturbances agree with the data of previous experiments performed under natural conditions and dealing with an "indirect" scenario of laminar-turbulent transition at high free-stream turbulence. It is shown that the leading edge of the plate does not play a decisive role in the mechanism of growth of disturbances of this kind and the receptivity is non-local in nature.