Modélisation de fractures comme des interfaces avec des maillages non-conformes Résumé : Nous étudions un modèle d'écoulement dans milieu poreux contenant une fracture. Dans ce modèle, la fracture est représentée comme une interface entre sous-domaines, au sein de laquelle des équations spécifiques doivent être résolues. Dans le présent article, nous analysons le problème discret, en faisant l'hypothèse que le maillage de la fracture et les maillages des sous-domaines sont complètement indépendants, mais respectent toutefois la géométrie de la fracture. Nous montrons que malgré cette non-conformité, le premier ordre de convergence est conservé pour les éléments finis mixtes de Raviart-Thomas(-Nedelec) de plus bas degré. Des simulations numériques confiment ce résultat. Mots-clés : fractures, barrières, éléments finis mixtes, écoulement en milieu poreux, maillages non-conformes

Abstract:In this report we are concerned with modeling single phase ow in a medium with known fractures. In particular we are interested in the case in which the ow rate in the fractures is large enough to make it appropriate to use Forchheimer's law for modeling the ow in the fractures even though the ow in the surrounding domain is such that Darcy's law is adequate. We describe a model in which the fractures are treated as interfaces. We also consider the case of intersecting fractures and the case of nonconforming meshes.

International audience We propose a numerical model for the flow of a single phase,incompressible fluid in a porous medium with fractures. In this model, the flow obeys Forchheimer's law in the fracture and Darcy's law in the rock matrix. Nous proposons un modèle numérique d'un écoulement monophasique d'un fluide incompressible dans un milieu poreux fracturé. Les lois d'écoulement sont celle de Forchheimer dans la fracture et de Darcy dans la matrice rocheuse.

Physics for medical students is perceived as a sophisticated subject. The sophistication, however, does not lie in the physics concepts themselves or students’ comprehension of the subject, but it is more often related to the ineffectiveness of techniques applied to teach the subject. This study investigates the effect of the Jigsaw technique, a highly structured form of cooperative learning, on the academic achievement of first-year medical students in learning physics. A quasi-experimental research approach with a pretest-posttest design was employed to conduct the study with a purposive randomly selected sample of fifty students made up of twenty-five students in the control group and twenty-five students in the experimental group. The control group was taught using traditional lectures, while the experimental group was taught using the Jigsaw technique which involved students working actively to map the concepts of nuclear radiation in diagnosis and therapy. A comprehensive statistical analysis, which included a Shapiro’s test, paired sample t-test, independent sample t-test, average gain factor, and size effect calculations, was used to test the research hypotheses. The findings of this study showed that there was a statistically significant difference (P < 0.05) between the post-test scores of students exposed to the Jigsaw cooperative learning technique and those who were not. In addition, it was deduced by the educator (first author) that the students were actively engaged with the topic material, took more responsibility for their performance in the activity, learned how to map the radiation physics concepts, and explored a new learning environment that enabled them to use their higher-order thinking skills to solve medical physics problems.

No abstract