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Investigation of the fluid flow in an isolated rotor-stator system with a peripheral opening

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Science China(Physics,Mechanics & Astronomy) 2013年第4期56卷 745-754页

作者： DEBUCHY Roger ABDEL NOUR Fadi NAJI Hassane bois gérard Laboratoire génie Civil & géo-Environnement (LgCgE- EA 4515) UArtois/FSA Béthune F-62400 Béthune France Université Lille Nord de France F-59000 Lille France Damascus University Department of Water Engineering Damascus Syria LML-PRES Lille Nord de France Arts et Métiers ParisTech Lille France

This paper deals with an experimental, theoretical and numerical study of a turbulent flow with separated boundary layers between a rotor and a stator. The system is not subjected to any superimposed radial flow. The periphery of the cavity is opened to the atmosphere so that the solid body rotation for infinite discs is not always observed. Emphasis was placed on develop- ment of an asymptotic approach and a step-by-step method to compute the radial distribution of the core swirl ratio and the static pressure on the stator side. The theory also includes the radial and axial velocities in the core region. The numerical simulation has been conducted with the commercial CFD code Fluent 6.1. The k- SST turbulence model is used, with the assumption of 2D-axisymmetric and steady flow. CFD validations have been performed by comparison of the numerical results with the corresponding theoretical results. Numerical and experimental results are in good agreement with analytical solutions.

关键词： rotor-stator cavity analytical solution numerical simulations k- SST turbulence model

Stepping up after spinal cord injury:negotiating an obstacle during walking

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Neural Regeneration Research 2025年第7期20卷 1919-1929页

作者： Alain Frigon Charly g.Lecomte Department of Pharmacology-Physiology Faculty of Medicine and Health SciencesUniversitéde SherbrookeCentre de recherche du Centre Hospitalier Universitaire de SherbrookeSherbrookeQCCanada

Every day walking consists of frequent voluntary modifications in the gait pattern to negotiate *** spinal cord injury,stepping over an obstacle becomes *** over an obstacle requires sensorimotor transformations in several structures of the brain,including the parietal cortex,premotor cortex,and motor *** information and planning are transformed into motor commands,which are sent from the motor cortex to spinal neuronal circuits to alter limb trajectory,coordinate the limbs,and maintain *** spinal cord injury,bidirectional communication between the brain and spinal cord is disrupted and animals,including humans,fail to voluntarily modify limb trajectory to step over an ***,in this review,we discuss the neuromechanical control of stepping over an obstacle,why it fails after spinal cord injury,and how it recovers to a certain extent.

关键词： biomechanics locomotion neurophysiology obstacle negotiation spinal cord injury

Numerical Shock Viscosity for Impact Analysis Using ALE Formulation

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Computer Modeling in Engineering & Sciences 2018年第10期117卷 91-107页

作者： Souli Mhamed Paul Du bois Essam Al-Bahkali Universitéde Lille1 Unitéde Mécanique de Lille UMR CNRS 8107France Consulting Engineer Troy MichiganUSA Mechanical Engineering Department King Saud UniversityP.O.Box 80011421 RiyadhSaudi Arabia

When the simulation takes account of dissipative mechanisms,*** conduction and viscosity,the shocks become smeared out to produce thin layers of rapidly and continuously varying energy,density,pressure and velocity rather than discrete surfaces of mathematical *** the mid twentieth century,Von Neumann and Richtmyer suggested the use of a viscous pressure term(bulk viscosity)in the equilibrium equations for ideal gases in order to examine the shock while avoiding numerical oscillations at the shock *** the bulk viscosity is included in the conservation equations,the comprehensive physics present a continuous solution satisfying the Rankine-Hugoniot ***,the published literature includes few engineering and research studies presenting the novel equilibrium equations in which the incorporation of bulk viscosity generates a continuous solution in keeping with conservation *** present work is aimed at demonstrating that the artificial bulk viscosity defined by Von Neumann and Richtmyer is also applicable to fluids described by a density-linear equation of state,that the novel equations present a continuous solution,and that a shock layer of the same order as the computational grid is *** the method has been employed and mathematically proven for onedimensional flow,it would seem to be just as relevant to the analysis of more complex flow dynamics and fluid structure interactions via an application of the Arbitrary Lagrangian Eulerian(ALE)formulation.

关键词： Shock wave fluid structure interaction ALE

Numerical and experimental comparison of the vaned diffuser interaction inside the impeller velocity field of a centrifugal pump

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Science China(Technological Sciences) 2011年第2期54卷 286-294页

作者： ATIF Abdelmadjid BENMANSOUR Saad bois gerard DUPONT Patrick Laboratory of Advanced Mechanics FGMGP/USTHBBP32 El Alia16111AlgerAlgeria Laboratory of Mechanics of Lille ENSAM-Lille8 Bd Louis XIV59046LilleFrance Laboratory of Mechanics of Lille EC-LilleBP48 Villeneuve d’Ascq59651LilleFrance

The paper refers to the analysis of interactions between the impeller and the vaned diffuser based on the air model of a radial flow *** study deals with a numerical simulation of the flow for a full 360°entire impeller and *** task is carried out closely under the design operating conditions and for one particular position of the impeller blade with respect to the diffuser *** all the results,the focus is mainly on the flow pattern at the exit part inside the impeller facing the diffuser *** results are compared to the available PIV measurements.

关键词： centrifugal pump impeller vaned diffuser rotor-stator interaction

Bioelectronic medicine in modulation of cortical spreading depolarization and beyond

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Neural Regeneration Research 2025年第2期20卷 481-482页

作者： Khaled Alok Timothy g.White Chunyan Li Department of Neurosurgery Donald and Barbara Zucker School of Medicine at Hofstra/NorthwellHempsteadNYUSA Translational Brain Research Laboratory The Feinstein Institutes for Medical ResearchManhassetNYUSA

Bioelectronic interventions,specifically trigeminal nerve st imulat ion(TNS),have attracted considerable attention in conditions where cortical spreading depolarizations(CSDs)accompanied by compromised cerebral perfusion may exacerbate neurological *** pharmacological interventions have demonstrated initial potential in addressing CSDs,a standardized treatment approach has not yet been *** objective of this perspective is to explore emerging bioelectronic methodologies for addressing CSDs,particularly emphasizing TNS,and to underscore TNS’s capacity to enhance neurovascular coupling and cerebral perfusion.

关键词： cerebral perfusion electronic

Impact of Zika virus non-structural protein mutations on hippocampal damage

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Neural Regeneration Research 2025年第8期20卷 2307-2308页

作者： Larissa M.g.Cassiano Roney S.Coimbra Neurogenômica/Imunopatologia Instituto RenéRachouFiocruzBelo HorizonteBrazil Departamento de Bioquímica e Imunologia Instituto de Ciências BiológicasUniversidade Federal de Minas GeraisBelo HorizonteBrazil

The Zika virus(ZIKV),a member of the Flaviviridae family,attracted worldwide attention for its connection to severe neurological effects,notably microcephaly in newborns,first reported during the 2015 epidemic in ***,its impact goes beyond fetal and neonatal abnormalities,also affecting the central nervous system(CNS)in both children and adults,leading to enduring cognitive and behavioral impairments.

关键词： damage fetal neonatal

Comparisons between numerical calculations and measurements in vaned diffuser of SHF impeller

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排灌机械工程学报 2013年第12期31卷 1013-1020页

作者： Annie-Claude Bayeul-Lainé Patrick Dupont giovanna Cavazzini Patrick Cherdieu Antoine Dazin gérard bois Olivier Roussette Laboratoire de Mécanique de Lille(UMR CNRS 8107) Arts et Métiers ParisTech Laboratoire de Mécanique de Lille(UMR CNRS 8107) Ecole Centrale de LilleVilleneuve D'Ascq Cedex 59651France Department of Industrial Engineering University of Padova

The paper presents analysis of the performance and the internal flow behaviour in the vaned diffuser of a radial flow pump using PIV(particle image velocimetry)and pressure probe *** measurements have already been performed at middle height inside one diffuser channel passage for a given speed of rotation and various mass flow *** results have been already presented in several previous *** experiments have been performed using a three-hole pressure probe traverses from hub to shroud diffuser width at different radial locations between the two diffuser geometrical *** simulations are also realized with the commercial codes Star CCM+7.02.011 and *** rotor and fully unsteady calculations of the whole pump have been *** between numerical results,previous experimental PIV results and new probe traverses one's are presented and discussed for one mass flow *** this respect,a first attempt to take into account fluid leakages between the rotating and fixed part of the pump has been checked since it may affects the real flow structure inside the diffuser.

关键词： vaned diffuser radial flow pump unsteady flow numerical calculations particle image velocimetry(PIV) three-hole probe

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径向导叶内流动分离特性的试验研究和控制

实验流体力学 2015年第6期29卷 48-53,78页

作者：司乔瑞袁寿其 Patrick Cherdieu gérard bois 江苏大学国家水泵及系统工程技术研究中心江苏镇江212013 法国国立高等工程技术大学LML实验室里尔59000

采用接触式探针和粒子图象测速技术(PIV)对导叶式离心泵径向导叶内流场的流动特性进行了研究。基于圆柱形微型三孔探针测试结果对5种流量下导叶的压力恢复能力进行了评估,测孔位置覆盖了导叶进出口截面和主线截面。压力恢复系数的理论... 详细信息

采用接触式探针和粒子图象测速技术(PIV)对导叶式离心泵径向导叶内流场的流动特性进行了研究。基于圆柱形微型三孔探针测试结果对5种流量下导叶的压力恢复能力进行了评估,测孔位置覆盖了导叶进出口截面和主线截面。压力恢复系数的理论值和试验值表明当流量大于导叶设计流量时导叶内产生了较大的静压损失。2C/2DPIV可视化试验的研究结果表明大流量下导叶叶片压力面发生了流动分离。设计了不同参数组合的涡流发生器来对流动分离现象进行控制,试验研究了6种方案对模型泵大流量工况下性能的影响,获得一组最佳方案,并分析了采用该方案后导叶内的流动特性。

关键词：离心泵径向导叶流动分离探针 PIV 涡流发生器

Printing accuracy tracking with 2D optical microscopy and super-resolution metamaterial-assisted 1D terahertz spectroscopy

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npj Flexible Electronics 2020年第1期4卷 178-184页

作者： Mariia Zhuldybina Xavier Ropagnol Chloébois Ricardo J.Zednik François Blanchard Département de génieélectrique École de technologie supérieure(ÉTS)MontréalQCCanada Institut national de la recherche scientifique Énergiematériaux et télécommunications(INRS-EMT)VarennesQCCanada Institut des Communications graphiques et de l’imprimabilité MontréalQCCanada Collège Ahuntsic MontréalQCCanada Département de génie mécanique École de technologie supérieure(ÉTS)MontréalQCCanada

Printable electronics is a promising manufacturing technology for the potential production of low-cost flexible electronic devices,ranging from displays to active *** is known that rapid printing of conductive ink on a flexible substrate is vulnerable to several sources of variation during the manufacturing ***,this process is still not being subjected to a quality control method that is both non-invasive and in *** address this issue,we propose controlling the printing accuracy by monitoring the spatial distribution of the deposited ink using terahertz(THz)*** parameters studied are the printing speed of an industrial roll-to-roll press with flexography printing units and the pre-calibration compression,or expansion factor,for a pattern printed on a flexible plastic *** pattern,which is carefully selected,has Babinet’s electromagnetic transmission properties in the THz frequency *** validate our choice,we quantified the geometric variations of the printed pattern by visible microscopy and compared its accuracy using one-dimensional THz *** study shows a remarkable agreement between visible microscopic observation of the printing performance and the signature of the THz ***,under specific conditions,one-dimensional(1D)THz information from a resonant pattern can be more accurate than two-dimensional(2D)microscopy *** result paves the way for a simple strategy for non-invasive and contactless in situ monitoring of printable electronics production.

关键词： printing visible pattern