Abstract: This article investigates the experimental results of a sweptwing model in a wind tunnel by means of the linear stability theory. It is discovered that different wavelengths of the crossflow stationary waves in the 3D boundary layer exhibite different evolutionary trends of disturbance. The largest amplificatory wavelength in this experimental situation, found through analysis and numerical calculation, is 4.0 mm, which is validated by Naphthalene visualization. This wavelength is successfully introduced to the leading edge of the sweptwing by an artificial roughness area created by the silkscreen technique, which affectes the 3D boundary layer transition just as predicted.

Key words: linear stability theory, swept wing, crossflow stationary wave, natural laminar transition, silkscreen, roughness, transition control