Author(s): Hubert Chanson
Linked Author(s): Hubert Chanson
Keywords: Tidal bores; Theoretical analysis; Physical modelling; Laboratory experiments; Field measurements; Computational fluid dynamics; Numerical modeling; Environmental impact
Abstract: A tidal bore is a series of waves propagating upstream as the tidal flow turns to rising in a river mouth during the early flood tide. The application of continuity and momentum principles gives a complete solution of the ratio of the conjugate cross-section areas as a function of the upstream Froude number Fr1 = (U+V1) / (g×A1/B1) 1/2. Theoretical considerations are developed in terms of the effects of flow resistance and bed slope. Physically the tidal bore propagation induces a massive mixing of the natural system. Prototype observations highlighted that the tidal bore passage is associated with large fluctuations in water depth and instantaneous velocity components. Both experimental and numerical studies indicated the production of large coherent structures advected behind the tidal bore. The presence of such large-scale coherent structures indicated that a great amount of sediment materials could be placed into suspension and transported by the flood tide flow in a natural system. Future research into tidal bores should combine computational calculations combined with ad-hoc laboratory measurements, and it must be complemented by detailed field measurements in natural systems.
Year: 2013