Experimental Study of Water Film Dynamics Under Wind Shear and Gravity

Aircraft icing poses a serious threat to flight safety. Unfrozen impinging water on the surface of the aircraft will run back under the effect of high-speed airflow, altering liquid distribution and heat transfer characteristics. In this paper, a series of experiments are conducted over a wide range of wind speeds (Ua=17.8∼52.2  m/s), film Reynolds numbers (Ref=26∼128), and inclined angles (α=0, ±30, ±45  deg) to investigate the dynamics of thin water film on an aluminum substrate. The superficial morphology of the water film is investigated by a high-speed camera, and the instantaneous film thicknesses are measured by a laser focus displacement meter based on a confocal chromatic technique. The interface shape is found to consist of an underlying thin film and multiple scaled fluctuations; therefore, the results are divided into two parts for analysis: the mean film thickness and the root-mean-square thickness. A relationship between the mean film thickness and the wind speed, the film Reynolds number, t...