Investigations on high Reynolds number laminar flow airfoils

Abstract

For further operating-cost reduction on transport aircraft, drag reduction by extended laminar flow on wings and empennages is mandatory. With carefully designed airfoils, laminar flow can be achieved even at high Mach and Reynolds numbers and moderate sweep angles. With laminar airfoils the fuel consumption decreases on the order of 30%. Twoand three-dimensional stability theory seems to be a good tool for determining laminar-turbulent boudary-layer transition caused by Tollmien-Schlichting and crossflow instabilities, but it must be checked by extensive flight tests.