Laminar-Turbulent Transition in Three-Dimensional Boundary Layers

Mechanisms of laminar-turbulent transition in three-dimensional boundary layers are discussed. These include crossflow instability, attachment-line transition and Tollmien-Schlichting waves. Among these, the dominant mechanism is crossflow instability that is responsible for transition inswept-wing flows and it has been the subject of many studies owing to its significance in laminar flow control. The breakdown (to turbulence) mechanism for crossflow disturbances is explained and methods for controlling (delay) transition are discussed. We then describe results from a swept-wing transition flight experiment conducted at supersonic speeds. Computational analysis of the experimental results is also presented, which demonstrates the efficacy of transition prediction tools in complex flows.