Experimental investigation of shear-driven water film flows on horizontal metal plate
In this article, an experimental investigation has been conducted to characterize the instantaneous thickness of the surface water film driven by high-speed airflow pertinent to aerodynamic icing and anti-icing modeling. Non-intrusive results of the film flowing on a metal plate were obtained using the high-speed camera and confocal chromatic technique. The wind speed (Ua) ranges from 17.8 m/s to 52.2 m/s, and the film Reynolds number (Ref) ranges from 26 to 128. The effect of the high-speed airflow on the structure of the wave film was observed and analyzed qualitatively. A new correlation of the interfacial shear factor was proposed for the prediction of the average film thickness. The predictions were compared with the previous annular flow models by applying the dimensionless analysis method and a good agreement is achieved. The superficial roughness, characterized by root-mean-square of the thickness, was well-correlated using a piecewise linear function of the average film thickness. Furthermore, a comprehensive description of the superficial waves including spectrum analysis and division of film thickness data between underlying film and large waves was presented. Transformations of the wave frequency and amplitude with the wind speed and the film Reynolds number were also addressed.