caa a22 4500 606198776 CHVBK 20210128100935.0 cr unu---uuuuu 210128e20150501xx s 000 0 eng 10.1007/s00348-015-1955-1 doi (NATIONALLICENCE)springer-10.1007/s00348-015-1955-1 Two-dimensional mapping of falling water film thickness with near-infrared attenuation [Elektronische Daten] [J. Dupont, G. Mignot, H.-M. Prasser] We have developed an optical technique for the two-dimensional mapping of water film thickness. The technique is based on infrared light absorption. A near-infrared camera is used to capture the radiation returning from a surface illuminated by a halogen lamp. The attenuation of the back-scattered radiation is used as a measure for the thickness of the water film covering the surface. The method was calibrated using well-defined liquid films between a glass plate and the surface. Series of instantaneous, two-dimensional thickness profiles of wavy turbulent free-falling films along a vertical wall were measured at a frame rate of 200Hz. The evolution of complex flow patterns with three-dimensional instabilities such as long waves and capillary waves was observed under isothermal conditions. For the validation of the method, simultaneous independent measurements were taken together with an electrical high-speed liquid film sensor. Springer-Verlag Berlin Heidelberg, 2015 Dupont J. Paul Scherrer Institut (PSI), Villigen, Switzerland aut Mignot G. Paul Scherrer Institut (PSI), Villigen, Switzerland aut Prasser H.-M Paul Scherrer Institut (PSI), Villigen, Switzerland aut Experiments in Fluids Springer Berlin Heidelberg 56/5(2015-05-01), 1-16 0723-4864 56:5<1 2015 56 348 https://doi.org/10.1007/s00348-015-1955-1 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/s00348-015-1955-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Dupont J. Paul Scherrer Institut (PSI), Villigen, Switzerland aut NATIONALLICENCE 700 1- Mignot G. Paul Scherrer Institut (PSI), Villigen, Switzerland aut NATIONALLICENCE 700 1- Prasser H.-M Paul Scherrer Institut (PSI), Villigen, Switzerland aut NATIONALLICENCE 773 0- Experiments in Fluids Springer Berlin Heidelberg 56/5(2015-05-01), 1-16 0723-4864 56:5<1 2015 56 348