Abstract: | Transition in the boundary layer on a flat plate in a turbulent flow is investigated experimentally and theoretically. It is established that over a broad range of flow conditions (variation of the intensity and scale of the external turbulence, the angle of attack, the shape of the leading edge, etc.) transition takes place without the formation of Tollmien-Schlichting waves, and its initial stages, including the amplification of disturbances, are described by the linearized unsteady three-dimensional boundary layer equations without a pressure gradient.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 55–65, September–October, 1989.The authors are grateful to N. F. Polyakov, V. S. Kosorygin, and O. S. Ryzhov for useful discussions and to N. N. Bychkov and O. N. Konstantinovskii for assisting with the experiments. |