Development of the turbulence-resolving two-fluid approach for sediment transport applications
Supervisors
M. Julien Chauchat
M. Cyrille Bonamy
Abstract
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During extreme meteorological events such as storms, waves and currents generated by strong winds have for effect to mobilize sediment resting at the bottom of the sea and significantly modify the beach morphology. In the context of climate change, the frequency and the intensity of extreme meteorological events are expected to increase. Predicting the beach morphology evolution for intense flow conditions is therefore crucial for the development and protection of the coastal environment. In this thesis, a numerical modelling methodology for which the carrier phase and the dispersed phase composed of the particles are seen as continua (two-fluid approach) is developed to study the small scale mechanisms playing a role in intense sediment transport under waves. Simulations conducted in this thesis allowed to provide a deeper insight into the effects of the grain size and the wave shape on sediment transport. Furthermore, up to now, due to constraints related to the hypothesis made to derive the model, it was only applicable to configurations for which the particles have to be small compared with the smallest turbulent scales of the flow. To avoid this limitation a new correction model taking into account finite-size effects to extend the two-fluid model range of applicability is proposed in this thesis.