Investigations on the effect of free-stream turbulence on boundary layer transition

The various correlations for predicting boundary-layer transition under high free stream turbulence exhibit serious discrepancies. The problem is described and a program of work oriented to its resolution is discussed. The results presented are limited to the zero pressure gradient case and show good first order agreement with established data for transition inception and completion and for intermittency distribution. The results nevertheless raise the question of representation of the intermittency distribution by a universal distribution. Difficulties remain with the quest for similarity which relate to measurement and analysis techniques used to determine sampling time and transition inception.