Control of Laminar-Turbulent Transition on a Swept Wing Using Surface Microreliefs

The possibility of laminarization of flow around a swept wing using surface microreliefs in the form of riblets and separate plates (winglets) set at an angle to external streamlines is theoretically investigated. This relief is shown to reduce the crossflow velocity in the boundary layer due to a change in the direction of the near-wall streamlines. On the basis of very simple models based on an analysis of the relief period-averaged boundary layer flow an increase in the Reynolds number of laminar-turbulent transition obtained using the microrelief is estimated. The reasonable surface relief parameters for experimentally investigating the effectiveness of the proposed technique of controlling laminar-turbulent transition are determined.