Author(s): David Reungoat; Hubert Chanson; Claire E. Keevil

Linked Author(s): David Reungoat, Hubert Chanson, Claire Keevil

Keywords: Acoustic Doppler velocimetry; field measurements; Garonne River; tidal bore; large-scale structures; turbulence

Abstract: A tidal bore is an unsteady rapidly-varied open channel flow generated by the swift advance of the early flood tide in a funnel-shaped river estuary when the tidal range exceeds 4.5 to 6 m. This contribution presents a detailed field investigation conducted on the tidal bore of the Garonne River (France). The bore was undular and the bore's leading edge was followed by well-defined secondary waves, or whelps. The instantaneous ADV velocity data indicated large and rapid fluctuations of all velocity components during the tidal bore. Large Reynolds shear stresses were observed during and after the tidal bore passage. The investigation characterized some unusual transient turbulence caused by the bore propagation in a large river system, and the results suggested the advection of large-scale eddies in the wake of the bore front. The present study highlighted the need for detailed field measurements with fine temporal resolution, to characterize the highly unsteady rapidly-varied nature of tidal bore flows.

DOI: https://doi.org/10.1080/00221686.2015.1021717

Year: 2015