At APS-DFD 2011, we presented preliminary data of water microdroplet impact at velocities up to 100 m/s and droplet diameters from 12 to 100 $\mu$m. Now we place these results into context and use them to improve understanding of droplet spreading. The parameter range covers the transition from capillary-limited to viscosity-limited spreading of the impacting droplet. The maximum spreading radius is compared to several existing models. The model by Pasandideh-Fard et al. (1996) agrees well with the measured data, indicating the importance of a thin boundary layer just above the surface. Here, most of the viscous dissipation of the spreading droplet takes place. As explained by the initial air layer under the impacting droplet, a contact angle of 180 degrees is used as model input.
*Stichting Fundamenteel Onderzoek der Materie is acknowledged for funding
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Authors
Claas Willem Visser
Universiteit Twente
University of Twente, Physics of Fluids Group
Yoshiyuki Tagawa
University of Twente
Universiteit Twente
Chao Sun
University of Twente
Physics of Fluids group, University of Twente, Netherlands
Universiteit Twente
University of Twente, Physics of Fluids Group
University of Twente, Enschede, The Netherlands
Physics of Fluids Group, University of Twente, The Netherlands
Detlef Lohse
University of Twente
Physics of Fluids, University of Twente, Enschede
Physics of Fluids, University of Twente
Physics of Fluids group, University of Twente, Netherlands
Universiteit Twente
University of Twente, Physics of Fluids Group
University of Twente, Enschede, The Netherlands
Physics of Fluids Group, Faculty of Science and Technology, J.M. Burgers Center for Fluid Dynamics, and IMPACT Institute, University of Twente, NL
Physics of Fluids Group, University of Twente, The Netherlands
