## Articles de journaux |

Philippe Agaciak; Samir Yahiaoui; Madeleine Djabourov; Thierry Lasuye Dehydration and drying poly(vinyl)chloride (PVC) porous grains: 1. Centrifugation and drying in controlled humid atmospheres Article de journal Colloids and Surfaces A: Physicochemical and Engineering Aspects, 469 , p. 132 - 140, 2015, ISSN: 0927-7757. @article{Yahiaoui:2015bb, title = {Dehydration and drying poly(vinyl)chloride (PVC) porous grains: 1. Centrifugation and drying in controlled humid atmospheres}, author = {Philippe Agaciak and Samir Yahiaoui and Madeleine Djabourov and Thierry Lasuye}, url = {http://www.sciencedirect.com/science/article/pii/S0927775715000308}, doi = {http://dx.doi.org/10.1016/j.colsurfa.2015.01.012}, issn = {0927-7757}, year = {2015}, date = {2015-01-01}, journal = {Colloids and Surfaces A: Physicochemical and Engineering Aspects}, volume = {469}, pages = {132 - 140}, abstract = {Concentration of aqueous suspensions of solid particles (called slurries in industrial processes) is achieved by centrifugation at high accelerations and it is an important step in dry powder productions; dehydration precedes drying. In aqueous suspensions of porous particles, water is both the interstitial fluid, which disperses the particles and the imbibition fluid, which fills the pores inside particles. This is the case in the pastes of poly(vinyl)chloride (PVC) polymerized in suspensions after centrifugation. PVC grains are non-colloidal particles with diameters close to 150 Î¼m and variable inner porosity, which are synthetized in aqueous solutions using dispersants such as various poly(vinyl)alcohols (PVA). In this paper we determine the dehydration by centrifugation of different grades PVC suspensions with laboratory scale experiments. It is shown that the humid pastes reach a pendular state at high accelerations and that the compaction of the grains and their surface properties determine the final retention of the water by capillary forces. In such conditions, internal water, inside the pores of the grains can be eliminated only by evaporation. Drying was investigated in controlled relative humidity atmospheres (RH) in desiccators by measuring the equilibrium moisture content of the grains and the evaporation rates. The evaporation rate of the superficial water is similar to pure water and can be interpreted using Stefan's equation, whereas substantial differences exist between the total drying times of grades.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Concentration of aqueous suspensions of solid particles (called slurries in industrial processes) is achieved by centrifugation at high accelerations and it is an important step in dry powder productions; dehydration precedes drying. In aqueous suspensions of porous particles, water is both the interstitial fluid, which disperses the particles and the imbibition fluid, which fills the pores inside particles. This is the case in the pastes of poly(vinyl)chloride (PVC) polymerized in suspensions after centrifugation. PVC grains are non-colloidal particles with diameters close to 150 Î¼m and variable inner porosity, which are synthetized in aqueous solutions using dispersants such as various poly(vinyl)alcohols (PVA). In this paper we determine the dehydration by centrifugation of different grades PVC suspensions with laboratory scale experiments. It is shown that the humid pastes reach a pendular state at high accelerations and that the compaction of the grains and their surface properties determine the final retention of the water by capillary forces. In such conditions, internal water, inside the pores of the grains can be eliminated only by evaporation. Drying was investigated in controlled relative humidity atmospheres (RH) in desiccators by measuring the equilibrium moisture content of the grains and the evaporation rates. The evaporation rate of the superficial water is similar to pure water and can be interpreted using Stefan's equation, whereas substantial differences exist between the total drying times of grades. |

Philippe Agaciak; Samir Yahiaoui; Madeleine Djabourov; Thierry Lasuye Dehydration and drying poly(vinyl)chloride (PVC) porous grains: 2. Thermogravimetric analysis and numerical simulations Article de journal Colloids and Surfaces A: Physicochemical and Engineering Aspects, 470 , p. 120 - 129, 2015, ISSN: 0927-7757. @article{Yahiaoui:2015ab, title = {Dehydration and drying poly(vinyl)chloride (PVC) porous grains: 2. Thermogravimetric analysis and numerical simulations}, author = {Philippe Agaciak and Samir Yahiaoui and Madeleine Djabourov and Thierry Lasuye}, url = {http://www.sciencedirect.com/science/article/pii/S0927775715000394}, doi = {http://dx.doi.org/10.1016/j.colsurfa.2015.01.020}, issn = {0927-7757}, year = {2015}, date = {2015-01-01}, journal = {Colloids and Surfaces A: Physicochemical and Engineering Aspects}, volume = {470}, pages = {120 - 129}, abstract = {This paper analyzes the drying rates of humid porous grains of poly(vinyl)chloride PVC by thermogravimetry. Grains have variable volume fractions of pores, representing between 16 and 33% g water/g PVC, with pore sizes varying between 0.6 and 1 Î¼m. It is shown that the humid cakes exhibit three different drying rate regimes at constant temperature, characterizing evaporation of free water, of interstitial water and of water inside the pores. The constant rate period (CRP) and the falling rate period (FRP) of drying are clearly identified. The drying rates and drying times are presented in adimensional units by comparison with evaporation of pure water. The thermogravimetric analysis identifies a fraction of water which dries very slowly inside the pores. A method of quantifying the strongly bound water is presented. Numerical simulations of water evaporation were performed on a 2D array of channels and illustrate the contribution of geometrical effects (diameter of channels, tortuosity, etc.) in pore drying. Visual observations of the drying of droplets of solutions containing dispersants used in PVC synthesis show interesting patterns. The phase separated solutions of dispersants are analyzed and their role in drying is highlighted.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This paper analyzes the drying rates of humid porous grains of poly(vinyl)chloride PVC by thermogravimetry. Grains have variable volume fractions of pores, representing between 16 and 33% g water/g PVC, with pore sizes varying between 0.6 and 1 Î¼m. It is shown that the humid cakes exhibit three different drying rate regimes at constant temperature, characterizing evaporation of free water, of interstitial water and of water inside the pores. The constant rate period (CRP) and the falling rate period (FRP) of drying are clearly identified. The drying rates and drying times are presented in adimensional units by comparison with evaporation of pure water. The thermogravimetric analysis identifies a fraction of water which dries very slowly inside the pores. A method of quantifying the strongly bound water is presented. Numerical simulations of water evaporation were performed on a 2D array of channels and illustrate the contribution of geometrical effects (diameter of channels, tortuosity, etc.) in pore drying. Visual observations of the drying of droplets of solutions containing dispersants used in PVC synthesis show interesting patterns. The phase separated solutions of dispersants are analyzed and their role in drying is highlighted. |

Rabia, Aminallah; Yahiaoui, Samir; Djabourov, Madeleine; Feuillebois, FranÃ§ois; Lasuye, Thierry Optimization of the vane geometry Article de journal Rheologica Acta, 53 (4), p. 357â€“371, 2014, ISSN: 1435-1528. @article{Yahiaoui:2014b, title = {Optimization of the vane geometry}, author = {Rabia, Aminallah and Yahiaoui, Samir and Djabourov, Madeleine and Feuillebois, FranÃ§ois and Lasuye, Thierry}, url = {http://dx.doi.org/10.1007/s00397-014-0759-1}, doi = {10.1007/s00397-014-0759-1}, issn = {1435-1528}, year = {2014}, date = {2014-01-01}, journal = {Rheologica Acta}, volume = {53}, number = {4}, pages = {357--371}, abstract = {The use of nonstandard geometries like the vane is essential to measure the rheological characteristics of complex fluids such as non-Newtonian fluids or particle dispersions. For this geometry which is of Couette type, there is no analytical simple model defining the relation between the shear stress and the torque or relating the angular velocity to the shear rate. This study consists on calibrating a nonstandard vane geometry using a finite volume method with the Ansys Fluent software. The influence of geometrical parameters and rheological characteristics of the complex fluids are considered. First, the Newtonian fluid flow in a rotative vane geometry was simulated and a parametric model is derived therefrom. The results show an excellent agreement between the calculated torque and the measured one. They provide the possibility to define equivalent dimensions by reference to a standard geometry with concentric cylinders where the relationships between shear stress (resp. shear rate) and the torque (resp. the angular rotation) are classical. Non-Newtonian fluid flows obeying a power law rheology with different indices were then simulated. The results of these numerical simulations are in very good agreement with the preceding Newtonian-based model in some ranges of indices. The absolute difference still under 5 % provided the index is below 0.45. Finally, this study provides a calibration protocol in order to use nonstandard vane geometries with various heights, gaps, and distance to the cup bottom for measuring the rheology of complex fluids like shear thinning fluids and concentrated suspensions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The use of nonstandard geometries like the vane is essential to measure the rheological characteristics of complex fluids such as non-Newtonian fluids or particle dispersions. For this geometry which is of Couette type, there is no analytical simple model defining the relation between the shear stress and the torque or relating the angular velocity to the shear rate. This study consists on calibrating a nonstandard vane geometry using a finite volume method with the Ansys Fluent software. The influence of geometrical parameters and rheological characteristics of the complex fluids are considered. First, the Newtonian fluid flow in a rotative vane geometry was simulated and a parametric model is derived therefrom. The results show an excellent agreement between the calculated torque and the measured one. They provide the possibility to define equivalent dimensions by reference to a standard geometry with concentric cylinders where the relationships between shear stress (resp. shear rate) and the torque (resp. the angular rotation) are classical. Non-Newtonian fluid flows obeying a power law rheology with different indices were then simulated. The results of these numerical simulations are in very good agreement with the preceding Newtonian-based model in some ranges of indices. The absolute difference still under 5 % provided the index is below 0.45. Finally, this study provides a calibration protocol in order to use nonstandard vane geometries with various heights, gaps, and distance to the cup bottom for measuring the rheology of complex fluids like shear thinning fluids and concentrated suspensions. |

Mongruel,A.; Lamriben,C.; Yahiaoui,S.; Feuillebois,F. The approach of a sphere to a wall at finite Reynolds number Article de journal Journal of Fluid Mechanics, 661 , p. 229â€“238, 2010, ISSN: 1469-7645. @article{Yahiaoui:2010ab, title = {The approach of a sphere to a wall at finite Reynolds number}, author = {Mongruel,A. and Lamriben,C. and Yahiaoui,S. and Feuillebois,F.}, url = {http://journals.cambridge.org/article_S0022112010003459}, doi = {10.1017/S0022112010003459}, issn = {1469-7645}, year = {2010}, date = {2010-01-01}, journal = {Journal of Fluid Mechanics}, volume = {661}, pages = {229--238}, abstract = {ABSTRACT The approach to a wall of a non-Brownian rigid spherical particle, settling in a viscous fluid with a Reynolds number of the order of unity, is studied experimentally. Far from the wall, the fluid motion around the particle is driven by inertia and viscosity forces. The particle Stokes number is also of the order of unity, so that the particle motion far from the wall is driven by inertia. In the close vicinity of the wall, however, the particleâ€“wall hydrodynamic interaction decelerates the particle significantly. An interferometric device is used to measure the vertical displacement of a millimetric size spherical bead at distances from the wall smaller than 0.1 sphere radius, with a spatial resolution of 100 nm. For the range of impact Stokes number (St*, based on the limit velocity of the sphere in an unbounded fluid) explored here (up to St* < 5), the measurements reveal that a small region of negligible particle inertia still exists just prior to contact of the sphere with the wall. In this lubrication-like region, the particle velocity decreases linearly with decreasing particleâ€“wall distance and vanishes at contact, ruling out the possibility of a rebound. The vertical extent of this region decreases with increasing Stokes number and is e.g. only 10 Î¼m large at impact Stokes number St* < 5.}, keywords = {}, pubstate = {published}, tppubtype = {article} } ABSTRACT The approach to a wall of a non-Brownian rigid spherical particle, settling in a viscous fluid with a Reynolds number of the order of unity, is studied experimentally. Far from the wall, the fluid motion around the particle is driven by inertia and viscosity forces. The particle Stokes number is also of the order of unity, so that the particle motion far from the wall is driven by inertia. In the close vicinity of the wall, however, the particleâ€“wall hydrodynamic interaction decelerates the particle significantly. An interferometric device is used to measure the vertical displacement of a millimetric size spherical bead at distances from the wall smaller than 0.1 sphere radius, with a spatial resolution of 100 nm. For the range of impact Stokes number (St*, based on the limit velocity of the sphere in an unbounded fluid) explored here (up to St* < 5), the measurements reveal that a small region of negligible particle inertia still exists just prior to contact of the sphere with the wall. In this lubrication-like region, the particle velocity decreases linearly with decreasing particleâ€“wall distance and vanishes at contact, ruling out the possibility of a rebound. The vertical extent of this region decreases with increasing Stokes number and is e.g. only 10 Î¼m large at impact Stokes number St* < 5. |

Yahiaoui, Samir; Feuillebois, FranÃ§ois Lift on a sphere moving near a wall in a parabolic flow Article de journal Journal of Fluid Mechanics, 662 , p. 447â€“474, 2010, ISSN: 1469-7645. @article{Yahiaoui:2010bb, title = {Lift on a sphere moving near a wall in a parabolic flow}, author = {Yahiaoui, Samir and Feuillebois, FranÃ§ois}, url = {http://journals.cambridge.org/article_S0022112010003307}, doi = {10.1017/S0022112010003307}, issn = {1469-7645}, year = {2010}, date = {2010-01-01}, journal = {Journal of Fluid Mechanics}, volume = {662}, pages = {447--474}, abstract = {ABSTRACT : The lift on a solid sphere moving along a wall in a parabolic shear flow is obtained as a regular perturbation problem for low Reynolds number when the sphere is in the inner region of expansion. Comprehensive results are given for the 10 terms of the lift, which involve the sphere translation and rotation, the linear and quadratic parts of the shear flow and all binary couplings. Based on very accurate earlier results of a creeping flow in bispherical coordinates, precise results for these lift terms are obtained for a large range of sphere-to-wall distances, including the lubrication region for sphere-to-wall gaps down to 0.01 of a sphere radius. Fitting formulae are also provided in view of applications. The migration velocity of an inertialess spherical particle is given explicitly, for a non-rotating sphere with a prescribed translation velocity and for a freely moving sphere in a parabolic shear flow. Values of the lift and migration velocity are in good agreement with earlier results whenever available.}, keywords = {}, pubstate = {published}, tppubtype = {article} } ABSTRACT : The lift on a solid sphere moving along a wall in a parabolic shear flow is obtained as a regular perturbation problem for low Reynolds number when the sphere is in the inner region of expansion. Comprehensive results are given for the 10 terms of the lift, which involve the sphere translation and rotation, the linear and quadratic parts of the shear flow and all binary couplings. Based on very accurate earlier results of a creeping flow in bispherical coordinates, precise results for these lift terms are obtained for a large range of sphere-to-wall distances, including the lubrication region for sphere-to-wall gaps down to 0.01 of a sphere radius. Fitting formulae are also provided in view of applications. The migration velocity of an inertialess spherical particle is given explicitly, for a non-rotating sphere with a prescribed translation velocity and for a freely moving sphere in a parabolic shear flow. Values of the lift and migration velocity are in good agreement with earlier results whenever available. |

Feuillebois, FranÃ§ois; Yahiaoui, Samir Dilute Suspensions near Walls Article de journal AIP Conference Proceedings, 1067 (1), p. 15-27, 2008. @article{Yahiaoui:2008bb, title = {Dilute Suspensions near Walls}, author = {Feuillebois, FranÃ§ois and Yahiaoui, Samir}, url = {http://scitation.aip.org/content/aip/proceeding/aipcp/10.1063/1.3030783}, doi = {http://dx.doi.org/10.1063/1.3030783}, year = {2008}, date = {2008-01-01}, journal = {AIP Conference Proceedings}, volume = {1067}, number = {1}, pages = {15-27}, abstract = {A precise account of particle-wall hydrodynamic interactions is important for modelling the motion of dilute suspensions near walls. Particles considered here are solid, spherical and small enough for the Reynolds number of the flow around each particle to be small compared with unity. At first order in Reynolds number, Stokes equations apply. Ambient flow fields are expressed as polynomials in terms of the coordinates. Various flow fields perturbed by a spherical particle near a wall may be superimposed by linearity of Stokes equations. Their solutions are recalled; they were calculated with the bispherical coordinates technique, providing precise results for the drag and torque on a particle. For particles in a gas, particle inertia may be important even though for low Reynolds number fluid inertia is negligible. It is shown that collision of a particle on a wall is not possible in creeping flow even if particle inertia is not negligible. At second order in the low Reynolds number, a small fluid inertia appears. For a sphere moving in a linear shear flow and a quadratic shear flow along a wall, there is then a lift force. The various pair couplings between sphere translation, rotation and the shear flows provide contributions to the lift. For a particle moving normal to a wall in a quiescent fluid at constant velocity, fluid inertia provides steady and unsteady contributions to the drag force. }, keywords = {}, pubstate = {published}, tppubtype = {article} } A precise account of particle-wall hydrodynamic interactions is important for modelling the motion of dilute suspensions near walls. Particles considered here are solid, spherical and small enough for the Reynolds number of the flow around each particle to be small compared with unity. At first order in Reynolds number, Stokes equations apply. Ambient flow fields are expressed as polynomials in terms of the coordinates. Various flow fields perturbed by a spherical particle near a wall may be superimposed by linearity of Stokes equations. Their solutions are recalled; they were calculated with the bispherical coordinates technique, providing precise results for the drag and torque on a particle. For particles in a gas, particle inertia may be important even though for low Reynolds number fluid inertia is negligible. It is shown that collision of a particle on a wall is not possible in creeping flow even if particle inertia is not negligible. At second order in the low Reynolds number, a small fluid inertia appears. For a sphere moving in a linear shear flow and a quadratic shear flow along a wall, there is then a lift force. The various pair couplings between sphere translation, rotation and the shear flows provide contributions to the lift. For a particle moving normal to a wall in a quiescent fluid at constant velocity, fluid inertia provides steady and unsteady contributions to the drag force. |

Pasol, Laurentiu; Chaoui, Mohamed; Yahiaoui, Samir; Feuillebois, FranÃ§ois Analytical solutions for a spherical particle near a wall in axisymmetrical polynomial creeping flows Article de journal Physics of Fluids, 17 (7), p. 073602, 2005. @article{Yahiaoui:2005ab, title = {Analytical solutions for a spherical particle near a wall in axisymmetrical polynomial creeping flows}, author = {Pasol, Laurentiu and Chaoui, Mohamed and Yahiaoui, Samir and Feuillebois, FranÃ§ois}, url = {https://hal.archives-ouvertes.fr/hal-00162692}, year = {2005}, date = {2005-01-01}, journal = {Physics of Fluids}, volume = {17}, number = {7}, pages = {073602}, publisher = {American Institute of Physics}, abstract = {Analytical solutions are presented for axisymmetric creeping flows around a spherical particle near a wall, when the unperturbed flow velocity varies as polynomial with the coordinates. The perturbed fluid velocity and pressure are calculated directly with the method of bipolar coordinates. They are obtained with a 10^(âˆ’16) precision, even for small gaps of the order of 10^(âˆ’6) sphere radius. For a constant unperturbed flow, the problem is equivalent to that of a sphere moving perpendicularly to a wall in a fluid at rest. An alternative indirect solution for the fluid velocity and pressure is obtained in this case from the solution of Brenner [Chem. Eng. Sci.16, 242 (1961)] and Maude [Brit. J. Appl. Phys.12, 293 (1961)] for the stream function. For a small gap between the sphere and the wall, the values of the pressure are compatible with the ones from the lubrication approximation but are systematically larger; this may be important for applications. Calculations are also performed when the unperturbed flow velocity is a polynomial of degree 2 and 3 in the coordinates, viz., for different types of stagnation point flows. Various flow structures are obtained, depending on the particle to wall distance. When the sphere approaches the wall, there is an increasing number of nested toroidal eddies, providing a link between the case of a single toroidal eddy when the sphere is far from the wall and the infinite set of Moffatt eddies in the gap between bodies in contact. The flow structure is analogous to that for two equal spheres in a uniform flow field, cf. Davis, Oâ€™Neill, Dorrepaal, and Ranger [J. Fluid Mech.77, 625 (1976)]. Precise results for the force on the sphere are provided.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Analytical solutions are presented for axisymmetric creeping flows around a spherical particle near a wall, when the unperturbed flow velocity varies as polynomial with the coordinates. The perturbed fluid velocity and pressure are calculated directly with the method of bipolar coordinates. They are obtained with a 10^(âˆ’16) precision, even for small gaps of the order of 10^(âˆ’6) sphere radius. For a constant unperturbed flow, the problem is equivalent to that of a sphere moving perpendicularly to a wall in a fluid at rest. An alternative indirect solution for the fluid velocity and pressure is obtained in this case from the solution of Brenner [Chem. Eng. Sci.16, 242 (1961)] and Maude [Brit. J. Appl. Phys.12, 293 (1961)] for the stream function. For a small gap between the sphere and the wall, the values of the pressure are compatible with the ones from the lubrication approximation but are systematically larger; this may be important for applications. Calculations are also performed when the unperturbed flow velocity is a polynomial of degree 2 and 3 in the coordinates, viz., for different types of stagnation point flows. Various flow structures are obtained, depending on the particle to wall distance. When the sphere approaches the wall, there is an increasing number of nested toroidal eddies, providing a link between the case of a single toroidal eddy when the sphere is far from the wall and the infinite set of Moffatt eddies in the gap between bodies in contact. The flow structure is analogous to that for two equal spheres in a uniform flow field, cf. Davis, Oâ€™Neill, Dorrepaal, and Ranger [J. Fluid Mech.77, 625 (1976)]. Precise results for the force on the sphere are provided. |

## ConfÃ©rences |

Agaciak, Philippe; Yahiaoui, Samir; Djabourov, Madeleine; Lasuye, Thierry; Branly, Marc Drying of pvc slurries by thermogravimetry 5500 - 5599 ConfÃ©rence 2012. @conference{Yahiaoui:2012b, title = {Drying of pvc slurries by thermogravimetry}, author = {Agaciak, Philippe and Yahiaoui, Samir and Djabourov, Madeleine and Lasuye, Thierry and Branly, Marc}, year = {2012}, date = {2012-01-01}, journal = {Drying Technology: : Proceedings of the 18th International Drying Symposium}, keywords = {}, pubstate = {published}, tppubtype = {conference} } |

## inproceedings |

Yahiaoui, Samir; Feuillebois, FranÃ§ois Effets inertiel et instationnaire pour les interactions sphÃ¨re-paroi Ã petit nombre de Reynolds Inproceedings AFM, Maison de la M'ecanique, 39/41 rue Louis Blanc-92400 Courbevoie, 2007. @inproceedings{Yahiaoui:2007b, title = {Effets inertiel et instationnaire pour les interactions sphÃ¨re-paroi Ã petit nombre de Reynolds}, author = {Yahiaoui, Samir and Feuillebois, FranÃ§ois}, year = {2007}, date = {2007-01-01}, journal = {18`eme Congr`es FranÃ§ais de M'ecanique (Grenoble 2007)}, publisher = {AFM, Maison de la M'ecanique, 39/41 rue Louis Blanc-92400 Courbevoie}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |

Yahiaoui, Samir; Feuillebois, FranÃ§ois Force de portance sur une petite sphÃ¨re dans un Ã©coulement parabolique au voisinage d'une paroi Inproceedings AFM, Maison de la M'ecanique, 39/41 rue Louis Blanc-92400 Courbevoie, 2005. @inproceedings{yahiaoui:2005bb, title = {Force de portance sur une petite sphÃ¨re dans un Ã©coulement parabolique au voisinage d'une paroi}, author = {Yahiaoui, Samir and Feuillebois, FranÃ§ois}, year = {2005}, date = {2005-01-01}, journal = {17Ã¨me CongrÃ¨s FranÃ§ais de M'ecanique (Grenoble 2007)}, publisher = {AFM, Maison de la M'ecanique, 39/41 rue Louis Blanc-92400 Courbevoie}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |

## ThÃ¨ses |

Yahiaoui, Samir Transport de petites particules par un Ã©coulement de fluide visqueux ThÃ¨se de doctorat Paris 6, 2008. @phdthesis{yahiaoui:2008, title = {Transport de petites particules par un Ã©coulement de fluide visqueux}, author = {Yahiaoui, Samir}, year = {2008}, date = {2008-01-01}, school = {Paris 6}, abstract = {Ce mÃ©moire contribue Ã l'Ã©tude des interactions hydrodynamiques particules-paroi dans un Ã©coulement Ã faible nombre de Reynolds. Divers Ã©coulements de Stokes axisymÃ©triques sont calculÃ©s pour une sphÃ¨re proche d'une paroi plane. On utilise ensuite les techniques de perturbation pour dÃ©terminer les forces hydrodynamiques : la force de traÃ®nÃ©e visqueuse inertielle et instationnaire pour le mouvement d'une sphÃ¨re normal Ã une paroi plane, la force de portance pour une sphÃ¨re en mouvement parallÃ¨le Ã une paroi dans diffÃ©rents Ã©coulements ambiant, sans aucune restriction sur la distance sÃ©parant la sphÃ¨re et la paroi. En rÃ©gime de lubrification, on apporte Ã©galement des corrections aux approximations des vitesses et pression du fluide dans le cas oÃ¹ la sphÃ¨re sÃ©dimente perpendiculairement Ã la paroi. }, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } Ce mÃ©moire contribue Ã l'Ã©tude des interactions hydrodynamiques particules-paroi dans un Ã©coulement Ã faible nombre de Reynolds. Divers Ã©coulements de Stokes axisymÃ©triques sont calculÃ©s pour une sphÃ¨re proche d'une paroi plane. On utilise ensuite les techniques de perturbation pour dÃ©terminer les forces hydrodynamiques : la force de traÃ®nÃ©e visqueuse inertielle et instationnaire pour le mouvement d'une sphÃ¨re normal Ã une paroi plane, la force de portance pour une sphÃ¨re en mouvement parallÃ¨le Ã une paroi dans diffÃ©rents Ã©coulements ambiant, sans aucune restriction sur la distance sÃ©parant la sphÃ¨re et la paroi. En rÃ©gime de lubrification, on apporte Ã©galement des corrections aux approximations des vitesses et pression du fluide dans le cas oÃ¹ la sphÃ¨re sÃ©dimente perpendiculairement Ã la paroi. |

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