Progress in Development of Amplitude Method of Transition Prediction on Swept Wing

Abstract

An amplitude method of laminar-turbulent transition prediction in the boundary layer on a swept wing was developed and tested. It is based on findings of amplitudes and spectra of steady and traveling cross-flow instability modes and Tollmien-Schlichting waves generated by surface roughness or free-stream turbulence. Transition criterion is based on crucial values of maximal or local amplitudes of these perturbations found from experiments. Statistical methods describing intermittency in transition zone from this criterion are proposed.