21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-3.3.4

CAPABILITIES OF SURFACE MEASUREMENT TECHNIQUES AND THEIR IMPACT ON MODERN WING-DESIGN AND ASSESSMENT

Nitsche W., Bose S., Haselbach F., Suttan J.
Technical University of Berlin, Germany

Keywords: shock, boundar layer, surface measurement techniques

Steady and unsteady surface measurement techniques for subsonic and transonic flows are surveyed emphasizing their capabilities on modern wing design and assessment. In this context, the present paper first investigates the accuracy of some existing sensor techniques for the determination of the mean wall shear stress (Preston Tube (CPM3), Surface Hot-Film, Obstacle Wire) in transonic flows, using a floating element balance as a reference. Additionally, the status and the capabilities of a number of improved surface measurement techniques (Surface Hot-Film Array, Piezo-Array, Liquid Crystals), which are necessary for the analysis of distributed flow phenomena on airfoils, like boundary layer (b.l.) transition, shock - b.l. interaction or separation, are demonstrated in wind tunnel as well as in in-flight tests. By this, different test cases are comparatively investigated using the mentioned techniques, in order to evaluate their capabilities for monitoring the boundary layer state on airfoils.

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