BOUNDARY-LAYER STABILITY ANALYSIS OF FLIGHT-MEASURED TRANSITION DATA 901809
Correlation of in-flight boundary-layer transition experiments with linear boundary-layer stability theory contributes both to the validation of the numerical methods as well as the analysis of the measured transition process. Transition results obtained in a recent flight experiment, in which the extent of laminar flow and the transition process on the wing of a business-jet fitted with an instrumented glove section were determined, are analyzed. The experiment was conducted at freestream Mach numbers from 0.55 to 0.82, chord Reynolds numbers from 10 to 20x106, and leading-edge sweep angles of 17° to 20°. The growth of both Tollmien-Schlichting and crossflow instabilities are predicted using the en method for several flight conditions and the calculated “n-factors” at transition onset are correlated. Comparison of the measured dominant boundary-layer disturbance frequencies and the predicted unstable frequencies shows fair agreement for several of the flight conditions studied.