Author(s): Márton Zsugyel, Sándor Baranya, K. Gábor Szabó and János Józsa
Linked Author(s):
Keywords: UAV; Lagrangian trajectory analysis; mixing; groyne; confluence
Abstract:
Complex flow structures in large rivers often occur, for instance in the vicinity of groyne fields or at river confluences. In the first case the eddy shedding at the tip of the groyne affects the mixing process as water or pollutant parcels may be trapped for a long time in the recirculation zone downstream of the groyne. At river confluences the different flow speed of the two rivers is the main reason of the occurance of complex flow structures, e.g. unsteady rolling up flow features, eddies formations, etc. The investigation at such complicated flow fields with Lagrangian methods based on the analysis of particle trajectories offers a novel approach to describe transport and mixing processes.
In this study the Lagrangian analysis of field measurements are presented at a river confluence. The measurement wastaken with a DJI Phantom3 Standard Unmanned Aerial Vehicle above the River Danube in Hungary. Different natural, biodegradable tracers were chosen, e.g. puffed wheat disks, lemons, water melon disks, etc., which floating on the surface were used for the Lagrangian analysis. These tracers were deployed continuously into both confluencing rivers (the Danube and the Mosoni-Danube).
An in house developed Large Scale Particle Tracking (LSPTV) algorithm was applied on the recorded video frames. Different Lagrangian descriptors were analized to characterize processes occuring at the river confluence.
Year: 2019