Une Nouvelle Pédagogie pour des Travaux Pratiques en Mécanique des Fluides

National audienceThe Fluid Mechanics Teaching Group of Ecole Centrale de Lyon introduced new teaching methods for the lab works of 2nd year students (eq. Master 1). Instead of a classical linear experiment on a dedicated rig, the students choose a scientific ant technical theme they illustrate on a panel of rigs and numerical simulations. During the first session, the students choose a theme and define objectives and concepts to illustrate, in conjunction with the theoretical classes. They also select appropriate experimental rigs and numerical simulations. During the next two sessions, they have to carry out the experiments and simulations, over the same configurations. Data are analyzed according to the objectives, combining experimental and numerical approaches. Finally, the work is synthesized through a report and a presentation during the last session. This talk is also a way to present the results to the other groups that studied different themes.L'Equipe d'Enseignement de Mécanique des Fluides de l'Ecole Centrale de Lyon pratique une nouvelle pédagogie pour les Travaux Pratiques dédiés aux élèves de 2ème année. Plutôt que de réaliser classiquement une expérience formatée sur une installation dédiée, les étudiants définissent eux-mêmes un thème scientifique et technique qu'ils illustrent grâce à un panel d'installations expérimentales et de simulations numériques. Lors d'une première séance, les étudiants choisissent leur thème d'étude et définissent des objectifs et des concepts à illustrer, en lien avec les enseignements théoriques dispensés. Ils identifient les installations expérimentales et les simulations utiles. Lors des deux séances intermédiaires, ils réalisent leurs expériences et des simulations numériques, menées sur les mêmes configurations. Les données traitées sont analysées en cohérence avec les objectifs prédéfinis, et en confrontant les approches numériques et expérimentales. La dernière séance est consacrée à la restitution. Un rapport écrit et un exposé oral constituent un exercice de synthèse. Par ailleurs, l'exposé oral est un vecteur de transmission des connaissances acquises, à l'adresse des étudiants ayant choisi un autre thème d'étude

Analysis of the Interrow Flow Field Within a Transonic Axial Compressor: Part 2—Unsteady Flow Analysis

ABSTRACT An analysis of the experimental data, obtained by laser two-focus anemometry in the IGV-rotor inter-row region of a transonic axial compressor, is presented with the aim of improving the understanding of the unsteady flow phenomena. A study of the IGV wakes and of the shock waves emanating from the leading edge of the rotor blades is proposed. Their interaction reveals the increase in magnitude of the wake passing through the moving shock. This result is highlighted by the streamwise evolution of the wake vorticity. Moreover, the results are analyzed in terms of a time averaging procedure and the purely time-dependent velocity fluctuations which occur are quantified. It may be concluded that they are of the same order of magnitude as the spatial terms for the inlet rotor flow field. That shows that the temporal fluctuations should be considered for the 3D rotor time-averaged simulations. NOMENCLATURE Symbols M R = relative Mach number N = number of blades P = measurement point location T = temporal period r U , U = rotor velocity vector, modulus V r , V = velocity vector, modulus X = some flow parameter or other r f = external forces n = co-ordinate normal to the shock p = pressure r = radial co-ordinate t = time z = axial co-ordinate r Ω , Ω = vorticity vector, modulus Θ = angular blade pitch α = absolute velocity angle ϕ = phase shift ω = rotation speed (radian/s) θ = azimuthal co-ordinate ρ = fluid density τ = turbulent and viscous stress tensor τ = co-ordinate tangent to the shock Superscripts -= time averaged valuẽ = spatial averaged value ' = time fluctuating value in the absolute frame * = spatial fluctuating value " = purely time-dependent fluctuating value Subscripts R = relative to the rotor n = component normal to the shock r = radial component r = rotor red = reduced value ref = reference value rel = relative to the rotor (for a time averaged process) s = stator θ = azimuthal co-ordinate τ = component tangent to the shock 1 = rotor inlet conditions INTRODUCTION A critical issue for the turbomachinery industry remains the timeaveraged simulation of multi-stage turbomachinery. Classical 3D multi-blade row simulation methods consist in connecting results of stationary calculations applied to isolated adjacent blade rows, the information between the rows usually being exchanged throug

Albiglutide and cardiovascular outcomes in patients with type 2 diabetes and cardiovascular disease (Harmony Outcomes): a double-blind, randomised placebo-controlled trial

Background: Glucagon-like peptide 1 receptor agonists differ in chemical structure, duration of action, and in their effects on clinical outcomes. The cardiovascular effects of once-weekly albiglutide in type 2 diabetes are unknown. We aimed to determine the safety and efficacy of albiglutide in preventing cardiovascular death, myocardial infarction, or stroke. Methods: We did a double-blind, randomised, placebo-controlled trial in 610 sites across 28 countries. We randomly assigned patients aged 40 years and older with type 2 diabetes and cardiovascular disease (at a 1:1 ratio) to groups that either received a subcutaneous injection of albiglutide (30–50 mg, based on glycaemic response and tolerability) or of a matched volume of placebo once a week, in addition to their standard care. Investigators used an interactive voice or web response system to obtain treatment assignment, and patients and all study investigators were masked to their treatment allocation. We hypothesised that albiglutide would be non-inferior to placebo for the primary outcome of the first occurrence of cardiovascular death, myocardial infarction, or stroke, which was assessed in the intention-to-treat population. If non-inferiority was confirmed by an upper limit of the 95% CI for a hazard ratio of less than 1·30, closed testing for superiority was prespecified. This study is registered with ClinicalTrials.gov, number NCT02465515. Findings: Patients were screened between July 1, 2015, and Nov 24, 2016. 10 793 patients were screened and 9463 participants were enrolled and randomly assigned to groups: 4731 patients were assigned to receive albiglutide and 4732 patients to receive placebo. On Nov 8, 2017, it was determined that 611 primary endpoints and a median follow-up of at least 1·5 years had accrued, and participants returned for a final visit and discontinuation from study treatment; the last patient visit was on March 12, 2018. These 9463 patients, the intention-to-treat population, were evaluated for a median duration of 1·6 years and were assessed for the primary outcome. The primary composite outcome occurred in 338 (7%) of 4731 patients at an incidence rate of 4·6 events per 100 person-years in the albiglutide group and in 428 (9%) of 4732 patients at an incidence rate of 5·9 events per 100 person-years in the placebo group (hazard ratio 0·78, 95% CI 0·68–0·90), which indicated that albiglutide was superior to placebo (p<0·0001 for non-inferiority; p=0·0006 for superiority). The incidence of acute pancreatitis (ten patients in the albiglutide group and seven patients in the placebo group), pancreatic cancer (six patients in the albiglutide group and five patients in the placebo group), medullary thyroid carcinoma (zero patients in both groups), and other serious adverse events did not differ between the two groups. There were three (<1%) deaths in the placebo group that were assessed by investigators, who were masked to study drug assignment, to be treatment-related and two (<1%) deaths in the albiglutide group. Interpretation: In patients with type 2 diabetes and cardiovascular disease, albiglutide was superior to placebo with respect to major adverse cardiovascular events. Evidence-based glucagon-like peptide 1 receptor agonists should therefore be considered as part of a comprehensive strategy to reduce the risk of cardiovascular events in patients with type 2 diabetes. Funding: GlaxoSmithKline

Analysis of the Interrow Flow Field Within a Transonic Axial Compressor: Part 2—Unsteady Flow Analysis

International audienc

Analysis of the Interrow Flow Field Within a Transonic Axial Compressor: Part 1—Experimental Investigation

International audienc

Treatment of L2F anemometer measurement volume distortions created by curved windows for turbomachinery applications

International audienc

L2F anemometry measurements of the inter-row flow field within a transonic axial compressor provided with curved windows

International audienc

Laser measurements in high speed compressors for rotor-stator interaction analysis

International audienc

Une Nouvelle Pédagogie pour des Travaux Pratiques en Mécanique des Fluides

National audienceThe Fluid Mechanics Teaching Group of Ecole Centrale de Lyon introduced new teaching methods for the lab works of 2nd year students (eq. Master 1). Instead of a classical linear experiment on a dedicated rig, the students choose a scientific ant technical theme they illustrate on a panel of rigs and numerical simulations. During the first session, the students choose a theme and define objectives and concepts to illustrate, in conjunction with the theoretical classes. They also select appropriate experimental rigs and numerical simulations. During the next two sessions, they have to carry out the experiments and simulations, over the same configurations. Data are analyzed according to the objectives, combining experimental and numerical approaches. Finally, the work is synthesized through a report and a presentation during the last session. This talk is also a way to present the results to the other groups that studied different themes.L'Equipe d'Enseignement de Mécanique des Fluides de l'Ecole Centrale de Lyon pratique une nouvelle pédagogie pour les Travaux Pratiques dédiés aux élèves de 2ème année. Plutôt que de réaliser classiquement une expérience formatée sur une installation dédiée, les étudiants définissent eux-mêmes un thème scientifique et technique qu'ils illustrent grâce à un panel d'installations expérimentales et de simulations numériques. Lors d'une première séance, les étudiants choisissent leur thème d'étude et définissent des objectifs et des concepts à illustrer, en lien avec les enseignements théoriques dispensés. Ils identifient les installations expérimentales et les simulations utiles. Lors des deux séances intermédiaires, ils réalisent leurs expériences et des simulations numériques, menées sur les mêmes configurations. Les données traitées sont analysées en cohérence avec les objectifs prédéfinis, et en confrontant les approches numériques et expérimentales. La dernière séance est consacrée à la restitution. Un rapport écrit et un exposé oral constituent un exercice de synthèse. Par ailleurs, l'exposé oral est un vecteur de transmission des connaissances acquises, à l'adresse des étudiants ayant choisi un autre thème d'étude