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Modelisation of the diffusive transport of algal blooms in a coastal environment using a stochastic method

Abstract : The aim of this PhD thesis was to develop a model to predict the motion of algae in sea waters along a coastline. The method chosen was to use a large Eulerian industrial code to model the mean flow, and add Lagrangian model to predict the motion of individual particles. This Lagrangian modelis a three-step model. In the first modelling step, the mean flow characteristics at the location of the particles (solid bodies modelling the algae) are extracted from the Eulerian model and imputed into a stochastic model to find the turbulent fluid velocities. These fluid velocities are used in the second step to solve for the solid body velocities, by solving for the drag, momentum, buoyant and Basset history forces. The final modelling step is to use these solid body velocities to calculate the trajectories of particles. An exact integrator method was then developed to solve for these equations. The model was then validated using two experiments. Firstly sphere of different size were released in fluids of different densities, where a stationary quasi-homogeneous turbulence. This turbulence was generated by oscillating a pair of grids. In the second experiment spherical particles were released in anon-homogeneous turbulent flow. This flow was achieved by partially obstructing a channel, so that a recirculation zone was generated. The particle transport model was then tested numerically using the simulations of a real flow along the coasts of Normandy where numerical particles representing algae were released
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Submitted on : Thursday, February 9, 2012 - 11:47:45 AM
Last modification on : Thursday, March 5, 2020 - 3:23:59 PM
Long-term archiving on: : Wednesday, December 14, 2016 - 5:27:38 AM


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  • HAL Id : pastel-00668176, version 1



Antoine Joly. Modelisation of the diffusive transport of algal blooms in a coastal environment using a stochastic method. Other [q-bio.OT]. Université Paris-Est, 2011. English. ⟨NNT : 2011PEST1088⟩. ⟨pastel-00668176⟩



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