Study of Transition in a High-Disturbance Environment

A theory is developed for a form of bypass transition that is induced by a high-disturbance environment and is used to study transitional e ows at low speeds. It employs an approach similar to that developed for natural transition. In this approach, transitional e ows are treated in a turbulencelike manner, and transition onset and extentaredeterminedaspartofthesolution.Itisshownthatthisform ofbypasstransitionisaresultofareceptivity mechanism, where the disturbance is characterized by a scale different from that of Tollmien ‐Schlichting waves. The theory is calibrated and validated by considering a range of low-speed e ows, with high freestream turbulence intensities, in the presence and absence of pressure gradients, referred to as the T3 test cases. Excellent agreement with measurements is indicated. It is suggested that transition in one of the test cases, T3C4, is a result of the bursting of a laminar separation bubble.