caa a22 4500 606197478 CHVBK 20210128100929.0 cr unu---uuuuu 210128e20150901xx s 000 0 eng 10.1007/s00348-015-2046-z doi (NATIONALLICENCE)springer-10.1007/s00348-015-2046-z An experimental investigation on the surface water transport process over an airfoil by using a digital image projection technique [Elektronische Daten] [Kai Zhang, Tian Wei, Hui Hu] In the present study, an experimental investigation was conducted to characterize the transient behavior of the surface water film and rivulet flows driven by boundary layer airflows over a NACA0012 airfoil in order to elucidate underlying physics of the important micro-physical processes pertinent to aircraft icing phenomena. A digital image projection (DIP) technique was developed to quantitatively measure the film thickness distribution of the surface water film/rivulet flows over the airfoil at different test conditions. The time-resolved DIP measurements reveal that micro-sized water droplets carried by the oncoming airflow impinged onto the airfoil surface, mainly in the region near the airfoil leading edge. After impingement, the water droplets formed thin water film that runs back over the airfoil surface, driven by the boundary layer airflow. As the water film advanced downstream, the contact line was found to bugle locally and developed into isolated water rivulets further downstream. The front lobes of the rivulets quickly advanced along the airfoil and then shed from the airfoil trailing edge, resulting in isolated water transport channels over the airfoil surface. The water channels were responsible for transporting the water mass impinging at the airfoil leading edge. Additionally, the transition location of the surface water transport process from film flows to rivulet flows was found to occur further upstream with increasing velocity of the oncoming airflow. The thickness of the water film/rivulet flows was found to increase monotonically with the increasing distance away from the airfoil leading edge. The runback velocity of the water rivulets was found to increase rapidly with the increasing airflow velocity, while the rivulet width and the gap between the neighboring rivulets decreased as the airflow velocity increased. Springer-Verlag Berlin Heidelberg, 2015 Zhang Kai Department of Aerospace Engineering, Iowa State University, 50010, Ames, IA, USA aut Wei Tian Department of Aerospace Engineering, Iowa State University, 50010, Ames, IA, USA aut Hu Hui Department of Aerospace Engineering, Iowa State University, 50010, Ames, IA, USA aut Experiments in Fluids Springer Berlin Heidelberg 56/9(2015-09-01), 1-16 0723-4864 56:9<1 2015 56 348 https://doi.org/10.1007/s00348-015-2046-z text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00348-015-2046-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zhang Kai Department of Aerospace Engineering, Iowa State University, 50010, Ames, IA, USA aut NATIONALLICENCE 700 1- Wei Tian Department of Aerospace Engineering, Iowa State University, 50010, Ames, IA, USA aut NATIONALLICENCE 700 1- Hu Hui Department of Aerospace Engineering, Iowa State University, 50010, Ames, IA, USA aut NATIONALLICENCE 773 0- Experiments in Fluids Springer Berlin Heidelberg 56/9(2015-09-01), 1-16 0723-4864 56:9<1 2015 56 348