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Article Dans Une Revue Coastal Engineering Année : 2021

Breaking bore roller characteristics: Turbulence statistics using optical techniques

Rui Shi
  • Fonction : Auteur
Hubert Chanson
  • Fonction : Auteur

Résumé

Surface wave breaking induces strong turbulence in the two-phase flow region. Detailed turbulence statistics were experimentally obtained using non-intrusive optical techniques in a breaking bore roller, at relatively large scale, with a bore Froude number Fr1 = 2.15 and Reynolds number Re = 2.3 × 105. These novel velocity data were ensemble-averaged based upon an instantaneous dataset of 24,320 images. In terms of the velocity field, the breaking bore roller was classified into three regions: the impinging jet, developing shear layer and flow reversal region. The vertical profiles of the longitudinal velocity data exhibited some self-similarity. The Reynolds stress data showed an anisotropic turbulent flow immediately downstream of the roller toe, and tended towards isotropy away from the roller toe. The vorticity data suggested that the breaking at the roller toe was responsible for the generation of vortices. The turbulent structures in the shear layer presented significantly smaller length and time scales with higher dissipation rate than other regions. A discussion between present turbulence statistical data and bubble dynamics from literature was developed. The comparison between present and past studies suggested a similarity in two-phase physical processes in the breaking roller region between the tidal bore, hydraulic jump, swash zone bore and breaking wave.
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Dates et versions

hal-03482870 , version 1 (16-12-2021)

Identifiants

Citer

Rui Shi, Xinqian Leng, Hubert Chanson. Breaking bore roller characteristics: Turbulence statistics using optical techniques. Coastal Engineering, 2021, 168, pp.103893. ⟨10.1016/j.coastaleng.2021.103893⟩. ⟨hal-03482870⟩
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