Numerical simulation of the flow rate effect on the evolution of a negatively buoyant water jet

A numerical simulation study was done on a penetrating pure water jet injected into another surrounding salt water miscible with negative buoyancy conditions. For the incompressible filtered Navier-Stokes equations and the sum of the fluid model volume, we used a transient Computational Fluid Dynamics (CFD) solver (VOF model). A finite volume discretization method using Open Source code given in Open Foam 2.3.0. was used to solve these equations. The flow has a significant impact in the laminar system on the evolution of the jet in terms of subsequent permanent phase as well as the transient regime

Computational study of the turbulent flow inside a heat exchanger using an incurved diffuser

L'objectif de ce travail est d'étudier l'écoulement turbulent dans un échangeur de chaleur contenant un diffuseur incurvée. Pour cela, nous avons développpé des simulations numériques avec un code CFD. Le modèle numérique est basé sur la résolution des équations de Navier-Stokes couplées avec le modèle de turbulence k-ε. Ces équations sont résolues par discrétisation volumes finis. Particulièrement, nous sommes intéressés à visualiser la température, la vitesse, la pression totale, la pression dynamique, la vorticité et les caractéristiques de la turbulence

Effect of the turbulence model on the aerodynamic structure around a Savonius wind rotor

Ce travail vise à étudier l'effet du modèle de turbulence sur les caractéristiques aérodynamiques de l'écoulement autour d'un rotor Savonius. Pour faire, nous avons développé une simulation numérique à l'aide du code commercial CFD Fluent. Le modèle numérique est basé sur la résolution des équations de Navier -Stokes. Ces équations sont résolues par une discrétisation volumes finis. Deux modèles de turbulence sont considérés : le modèle k-ԑ et le modèle k-ԑ RNG. Particulièrement, nous sommes intéressés à visualiser le champ de vitesse, la vitesse moyenne et la pression statique. L'accord entre nos résultats numériques et les résultats antérieurs confirme la validité de la méthode d'analyse adoptée

Cardiac tamponade and paroxysmal third-degree atrioventricular block revealing a primary cardiac non-Hodgkin large B-cell lymphoma of the right ventricle: a case report

<p>Abstract</p> <p>Introduction</p> <p>Primary cardiac lymphoma is rare.</p> <p>Case Presentation</p> <p>We report the case of a 64-year-old non-immunodeficient Caucasian man, with cardiac tamponade and paroxysmal third-degree atrioventricular block. Echocardiography revealed the presence of a large pericardial effusion with signs of tamponade and a right ventricular mass was suspected. Scanner investigations clarified the sites, extension and anatomic details of myocardial and pericardial infiltration. Surgical resection was performed due to the rapid impairment of his cardiac function. Analysis of the pericardial fluid and histology confirmed the diagnosis of non-Hodgkin large B-cell lymphoma. He was treated with chemotherapy.</p> <p>Conclusion</p> <p>The prognosis remains poor for this type of tumor due to delays in diagnosis and the importance of the site of disease.</p

Efficiency Analysis to evaluate a Breast Cancer Screening Campaign: A Case Study from Tunisia

International audienc

Myocardial deformation pattern in left ventricular non-compaction: Comparison with dilated cardiomyopathy

Left ventricular (LV) systolic dysfunction is the most frequent initial presentation of patient with LV noncompaction (NC). Our objectives were to evaluate myocardial contraction properties in patients with LVNC and the relationship of non-compacted segments with the degree of global and regional systolic deformation. We included 50 LVNC with an echocardiography and speckle imaging calculation of peak longitudinal strain (PLS). Each of the 16 LV myocardial segments was defined as NC (ratio NC/compacted layer > 2), borderline (NC/C 0–2) and compacted (NC/C = 0). Basal, median and apical strain values were calculated as the average of segmental strain values. For comparison a group of 50 patients with dilated cardiomyopathy (DCM) underwent the same measurements. There was no statistical difference between the 2 groups for any conventional LV systolic parameters. A characteristic deformation pattern was observed in LVNC with higher strain values in the LV apical segments (− 12.8 ± 5.9 vs − 10.7 ± 5.7) and an apical–basal ratio (1.52 ± 0.73 vs 1.12 ± 0.42, p < 0.001). There was no correlation between LV function and the degree of NC. Among 726 segments, compacta thickness was thinner in NC vs C segments (6.4 ± 1.4 vs 7.7 ± 1.8 mm, p < 0.05). There was no difference in WMS but regional strain values were significantly higher in NC compared to C segments (− 13.1 ± 6.1 vs − 10.2 ± 6.3, p < 0.05). Compared to DCM, LVNC presented with relatively preserved apical deformation as compared to basal segments. Lower regional deformation values in compacted segments confirm the concept that LVNC is a phenotypic marker of an underlying diffuse cardiomyopathy involving both C and NC myocardium