Unsteady Turbulence in a Tidal Bore: Field Measurements in the Garonne River in October 2013

摘要

A tidal bore is an unsteady rapidly-varied free-surface flowgenerated by the rapid rise in water elevation during the earlyflood tide, when the tidal range exceeds 4.5 to 6 m and thechannel bathymetry amplifies the flood tidal wave. This studydescribes a detailed field investigation conducted in the GaronneRiver (France). The tidal bore was undular on 19 October 2013and the bore front was followed by some well-defined whelps.The instantaneous velocity data indicated large and rapidfluctuations of all velocity components during the tidal bore.Large Reynolds shear stresses were observed during and after thetidal bore passage. Altogether the investigation characterisedsome unusual turbulence transient in a large river system.