I. Chapitre and . Étude-de-la-sédimentation-d, une particule isolée par biréfringence Après avoir étudié l'écoulement autour d'une particule isolée en sédimentation, nous avons observé la biréfringence induite par la sédimentation d'une particule isolée. Quand la loi tensio-optique est vérifiée, le tenseur des indices est proportionnel au tenseur des contraintes

. Dans-un-premier and . Temps, je décrirai le montage réalisé pour les expériences de biréfringence et sa calibration , dans un deuxième temps les résultats obtenus pour les différentes particules étudiées. Dans un troisième temps, une comparaison qualitative et quantitative entre les résultats de biréfringence et de

L. Particules-occultent-et-réémettent-en-partie-la-lumière-incidente, intensité lumineuse transmise dépend de la fraction volumique locale en particules. Pour cette étude, nous n'avons pas quantifié la relation entre l'intensité lumineuse transmise et la fraction volumique en particules. Les mesures présentées seront donc qualitatives mais renseignent sur les phénomènes observés. L'intensité lumineuse augmente quand la fraction volumique en particules décroît. L'inhomogénéité initiale sur toute la cellule de sédimentation est inférieure à 14%

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