Constellation, le dépôt institutionnel de l'Université du Québec à Chicoutimi

Résumé

When aircraft are kept on the ground for a significant period of time under cold precipitation, anti-icing fluids are used to prevent ice buildup. Unfortunately, at the time of takeoff, the residual fluid on wings modifies the boundary layer of the air and causes lift loss. The purpose of this work was to study the boundary-layer development of the air flowing above a horizontal flat plate covered with a de/anti-icing fluid film. The objective was to find the relationship between the air boundary layer and the geometric and dynamic characteristics of the air/fluid interface. This work consists of numerical and experimental studies. The experimental work contains a rheological study of the fluid and wind-tunnel tests on flat plates in order to describe the movement of the fluid during airflow acceleration. The numerical modeling is used for the prediction of the wave characteristics at the interface and for the determination of the integral relationships for rough boundary-layer conditions. The model of stability gave a good correlation between theory and experiment for the waveform at the air/fluid interface. A simple integral model determines an equivalent flat plate roughness that produces the same boundary layer as with the fluid. This equivalent roughness corresponds, in general, to the waveform, which indicates that the influence of the fluid seems to be only geometrical in nature.