caa a22 4500 606197214 CHVBK 20210128100928.0 cr unu---uuuuu 210128e20150601xx s 000 0 eng 10.1007/s00348-015-2006-7 doi (NATIONALLICENCE)springer-10.1007/s00348-015-2006-7 Interfacial shear stress measurement using high spatial resolution multiphase PIV [Elektronische Daten] [Matthieu André, Philippe Bardet] In multiphase flows, form drag and viscous shear stress transfer momentum between phases. For numerous environmental and man-made flows, it is of primary importance to predict this transfer at a liquid-gas interface. In its general expression, interfacial shear stress involves local velocity gradients as well as surface velocity, curvature, and surface tension gradients. It is therefore a challenging quantity to measure experimentally or compute numerically. In fact, no experimental work to date has been able to directly resolve all the terms contributing to the shear stress in the case of curved and moving surfaces. In an attempt to fully resolve the interface shear stress when surface tension gradients are negligible, high-resolution particle image velocimetry (PIV) data are acquired simultaneously on both sides of a water-air interface. The flow consists of a well-conditioned uniform and homogeneous water jet discharging in quiescent air, which exhibits two-dimensional surface waves as a result of a shear layer instability below the surface. PIV provides velocity fields in both phases, while planar laser-induced fluorescence is used to track the interface and obtain its curvature. To compute the interfacial shear stress from the data, several processing schemes are proposed and compared, using liquid and/or gas phase data. Vorticity at the surface, which relates to the shear stress through the dynamic boundary condition at the surface, is also computed and provides additional strategies for estimating the shear. The various schemes are in agreement within the experimental uncertainties, validating the methodology for experimentally resolving this demanding quantity. Springer-Verlag Berlin Heidelberg, 2015 André Matthieu Department of Mechanical and Aerospace Engineering, The George Washington University, Washington, DC, USA aut Bardet Philippe Department of Mechanical and Aerospace Engineering, The George Washington University, Washington, DC, USA aut Experiments in Fluids Springer Berlin Heidelberg 56/6(2015-06-01), 1-18 0723-4864 56:6<1 2015 56 348 https://doi.org/10.1007/s00348-015-2006-7 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/s00348-015-2006-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- André Matthieu Department of Mechanical and Aerospace Engineering, The George Washington University, Washington, DC, USA aut NATIONALLICENCE 700 1- Bardet Philippe Department of Mechanical and Aerospace Engineering, The George Washington University, Washington, DC, USA aut NATIONALLICENCE 773 0- Experiments in Fluids Springer Berlin Heidelberg 56/6(2015-06-01), 1-18 0723-4864 56:6<1 2015 56 348