Boundary layer measurements on a two-dimensional wing with flap and a comparison with calculations

Abstract

Measurements were performed on a wing flap configuration, which was so designed that flow separations occur nowhere, apart from a small laminar separation bubble on the wing nose. The measurements comprise surface pressure measurements, boundary layer and wake traverses at 16 stations, and flow visualization tests to establish the presence of separation bubbles and boundary layer transition regions. The data resolve the various flow phenomena sufficiently well to provide a significant test case for calculation methods for the flow around multi-element airfoils. Comparison with such a calculation method showed satisfactory agreement in many respects. A need for improved modelling was found to exist in some regions, particularly for the wing wake above the flap. The investigation has been performed under contract with the National Agency for Aerospace Programs (NIVR, contract numbers 1738 and 1812). Paper presented for the AGARD Symposium on "Turbulence boundary layers: experiments, theory and modelling", 24-25 September 1979, The Hague, The Netherlands.