caa a22 4500 477093299 CHVBK 20180405111520.0 cr unu---uuuuu 170330e19960301xx s 000 0 eng 10.1007/BF00191017 doi (NATIONALLICENCE)springer-10.1007/BF00191017 Weigand A. California Institute of Technology Graduate Aeronautical Laboratories, 91125, Pasadena, CA, USA aut Simultaneous mapping of the velocity and deformation field at a free surface [Elektronische Daten] [A. Weigand] The oblique interaction of a turbulent vortex ring with a clean water surface is experimentally investigated during the transition stage using Digital Particle Image Velocimetry (DPIV) and the shadowgraph technique to map the surface velocity and deformation field simultaneously. The transitional vortex-ring/free-surface interaction leads to the formation of a trifurcation pattern at the free surface. Similar to the laminar flow case, the vortex ring initially bifurcates into two symmetric and separately connected vortex loops. The turbulent break-up of those vortex loops results in the formation of longitudinal wake vortices that symmetrically connect to the surface and eventually lead to a trifurcation pattern. In the absence of large-deformation surface waves, the simultaneous DPIV and shadowgraph measurements reveal good agreement between the surface vorticity and deformation field for small- and large-scale vortical structures. The simultaneous measurement technique is not restricted to the qualitative shadowgraph visualization, but can be easily extended to quantitative methods such as grating-imaging techniques, Color Schlieren, or Color Surface Mapping (CSM) techniques. Springer-Verlag, 1996 Experiments in Fluids Springer-Verlag 20/5(1996-03-01), 358-364 0723-4864 20:5<358 1996 20 348 https://doi.org/10.1007/BF00191017 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00191017 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Weigand A. California Institute of Technology Graduate Aeronautical Laboratories, 91125, Pasadena, CA, USA aut NATIONALLICENCE 773 0- Experiments in Fluids Springer-Verlag 20/5(1996-03-01), 358-364 0723-4864 20:5<358 1996 20 348 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer