caa a22 4500 606198288 CHVBK 20210128100933.0 cr unu---uuuuu 210128e20150401xx s 000 0 eng 10.1007/s00348-015-1944-4 doi (NATIONALLICENCE)springer-10.1007/s00348-015-1944-4 Height-resolved velocity measurement of the boundary flow during liquid impact on dry and wetted solid substrates [Elektronische Daten] [Philipp Frommhold, Robert Mettin, Claus-Dieter Ohl] The impact of a droplet onto a dry or wet surface leads to a rapid formation of a shear flow at the boundary. We present a novel method to experimentally resolve this flow in time at different heights above the solid. The radial flow field close to the substrate is reconstructed by evaluation of streak images of fluorescent tracer particles in the liquid. By using a microscope objective with a narrow depth of field, it is possible to scan through the flow in thin horizontal layers of 5μm thickness. We focus on the flow close (≤40μm) to the boundary during the impact of elongated drops with diameters of 0.3-0.4mm and speeds in the range of 2-3ms−1. The spatial resolution is obtained from several individual events of the repeatable impact process and varying the focal plane. Fluorescent streaks formed by the suspended particles are recorded with high-speed photography at up to 20,000 frames per second. The impact of water and of ethanol is investigated both on dry glass and on glass covered with a thin film of the same liquid. Results are given as spatio-temporal maps of radial flow velocity at different heights, and the maximum shear stress at the substrate is evaluated. The implications of the results are discussed with respect to cleaning applications. Springer-Verlag Berlin Heidelberg, 2015 Frommhold Philipp Christian Doppler Laboratory for Cavitation and Micro-Erosion, Drittes Physikalisches Institut, Georg-August-University Göttingen, Göttingen, Germany aut Mettin Robert Christian Doppler Laboratory for Cavitation and Micro-Erosion, Drittes Physikalisches Institut, Georg-August-University Göttingen, Göttingen, Germany aut Ohl Claus-Dieter Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore aut Experiments in Fluids Springer Berlin Heidelberg 56/4(2015-04-01), 1-17 0723-4864 56:4<1 2015 56 348 https://doi.org/10.1007/s00348-015-1944-4 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/s00348-015-1944-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Frommhold Philipp Christian Doppler Laboratory for Cavitation and Micro-Erosion, Drittes Physikalisches Institut, Georg-August-University Göttingen, Göttingen, Germany aut NATIONALLICENCE 700 1- Mettin Robert Christian Doppler Laboratory for Cavitation and Micro-Erosion, Drittes Physikalisches Institut, Georg-August-University Göttingen, Göttingen, Germany aut NATIONALLICENCE 700 1- Ohl Claus-Dieter Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore aut NATIONALLICENCE 773 0- Experiments in Fluids Springer Berlin Heidelberg 56/4(2015-04-01), 1-17 0723-4864 56:4<1 2015 56 348