Experimental Study of Water Film Flow Dynamics on an Airfoil Under Wind Shear Force and Gravity

To investigate the flow dynamics of the water film on a NACA0012 airfoil surface under wind shear force and gravity, an experimental setup has been developed to examine the formation of a stable, continuous water film at wind speeds of 16–30 m/s and water film Reynolds numbers of 49.5–132.0. The water film exhibits distinct instantaneous fluctuations, with higher frequency and amplitude near the leading edge. These fluctuations are primarily influenced by wind speed and vary along the chord. The time-averaged water film thickness decreases first, then increases, and stabilizes near the trailing edge. The minimum thickness (about 0.1 mm) occurs near the airfoil's maximum thickness due to the high wind speed and large shear force in this region. The water film Reynolds number greatly affects thickness, especially near the trailing edge, where airflow boundary layer separation occurs. Based on the experimental results, a predictive model has been developed, showing good agreement with the measured chordwise thickness profile.