INTRODUCTORY ANALYSIS OF BOUNDARY-LAYER DEVELOPMENT ON DE ANTI-ICING FLUID/

When aircraft are kept on the ground for a significant period of time under cold precipitation, anti-icing fluids are used to prevent ice bu ildup. Unfortunately, at the time of takeoff, the residual fluid on wi ngs modifies the boundary layer of the air and causes lift loss. The p urpose of this work was to study the boundary-layer development of the air flowing above a horizontal flat plate covered with a de/anti-icin g fluid film. The objective was to find the relationship between the a ir 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 fl uid and wind-tunnel tests on flat plates in order to describe the move ment of the fluid during airflow acceleration. The numerical modeling is used for the prediction of the wave characteristics at the interfac e and for the determination of the integral relationships for rough bo undary-layer conditions. The model of stability gave a good correlatio n between theory and experiment for the waveform at the air/fluid inte rface. A simple integral model determines an equivalent nat plate roug hness that produces the same boundary layer as with the fluid. This eq uivalent roughness corresponds, in general, to the waveform, which ind icates that the influence of the fluid seems to be only-geometrical in nature.