Recent advances in eulerian and lagragian large_scale particle image velocimetry.

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Antoine Patalano, Carlos Marcelo García, Wernher Brevis, Tobias Bleninger, Nicolas Guillen, Lautaro Moreno, Andres Rodriguez

Thursday 2 july 2015

12:15 - 12:30h at Africa (level 0)

Themes: (T) Special session, (ST) Acoustic monitoring of flow, turbulence and river discharge

Parallel session: 11F. Special session: Acoustic monitoring of flow, turbulence and river discharge

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For decades, image based velocimetry techniques, both in the Eulerian and Lagrangian frame of references, have played an important role for the understanding of several environmental and hydraulics phenomena. The constant technological developments have made sensors more accessible to the end user, thus they are nowadays a viable option to perform measurements in a broad range of problems. There have been a scientific and engineering interest to use image based velocimetry techniques to describe large-scale phenomena and in particular, in fluvial hydraulics, to improve our understanding of natural and artificial large-scale open channel flows. This paper presents recent contributions, by the authors of this work, to the development and application of Large-Scale Particle Image Velocimetry (LSPIV) and Large-Scale Particle Tracking Velocimetry (LSPTV) . The work shows the results of the application of LSPIV to the measurement of flow discharges in Mountain Rivers of the Córdoba province in Argentina. These rivers are characterized by a high flow variability, mainly due to the occurrence of flash floodings. Due to the extreme flow condition during these events, the use of intrusive measurement technologies such as current meters or Acoustic Doppler Current Profiler (ADCP) is difficult due to the high risk for the integrity of instruments and operators. The LSPIV technique has been implemented using remote digital cameras mounted on a crane, and on an Unmanned Aerial Vehicle (UAV). The work also present the results of LSPTV in a large-scale physical model experiment. The development of a software for the application of both techniques is also described in this paper. In particular the pre and post-processing techniques implemented in the software are described. These techniques, such as data rectification and unsteady movements compensation, are crucial for the successful application of LSPIV and LSPTV in large-scale conditions.