27th Congress of International Council of the Aeronautical Sciences, 19 - 24 September 2010, Nice, France
Paper ICAS 2010-3.8.3

DETECTION OF LAMINAR-TURBULENT TRANSITION IN A FREE-FLIGHT EXPERIMENT USING THERMOGRAPHY AND HOT-FILM ANEMOMETRY

P. Schreivogel
Univ. of Dresden, Germany

Keywords: boundary-layer transition, free-flight, thermography, hot-film

During a student research project in summer 2008 free-flight experiments were carried out in order to detect laminar-turbulent transition in the boundary-layer of a gliders wing. The two-seated plane was equipped with an infrared camera on a tripod above the fuselage and hot-film gauges on the wing surface. The wall temperature distribution as well as a quasi-wall shear stress resulting from the anemometer output voltage were used for locating the transitional zone. A comparison of both techniques showed consistent results for stationary flight attitudes. Due to the high temporal resolution of the hot-film gauges, the influence of atmospheric turbulence on the transition location could be visualized. Regarding the measurements, the angle of attack and hence the pressure distribution are supposed to dominate the transition location on the examined airfoil.

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