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Numerical Haemodynamics in the Human Heart

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Book Series: Schriftenreihe des Instituts für Strömungsmechanik, Karlsruher Institut für Technologie ISSN: 21998868 ISBN: 9783731507574 Year: Volume: 3 Pages: VII, 180 p. DOI: 10.5445/KSP/1000080044 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Technology (General)
Added to DOAB on : 2019-07-28 18:37:01
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The characteristic vortex formation in the ventricles is believed to be affected at an early stage of heart diseases. First, post-processing of patient-specific data has to be standardised. The chosen methods, a combination of Eulerian and Lagrangian techniques, are characterised by means of necessary spatial and temporal resolutions. Second, the goal is to find the best cost-benefit approach for modelling of the mitral valve, as it affects vortex formation and progression in the left ventricle.

Untersuchung der Makro- und Mikromischung in kontinuierlich durchströmten Taylor-Vortex Reaktoren mit modifizierter Rotorgeometrie

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ISBN: 9783866444300 Year: Pages: 156 p. DOI: 10.5445/KSP/1000013130 Language: GERMAN
Publisher: KIT Scientific Publishing
Subject: Chemical Engineering
Added to DOAB on : 2019-07-30 20:01:58
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In der vorliegenden Arbeit wurde der Einfluss der Zylindergeometrie (zylindrisch; rippenförmig) auf die Mischcharakteristik eines kontinuierlich durchströmten Taylor-Vortex Reaktors untersucht. Hierfür wurde die Makro- und Mikromischung mittels Spurstoffversuchen, Messung des Rührenergieeintrages und einer chemischen Testreaktion bestimmt.

Shallow turbulent wake flows: momentum and mass transfer due to large-scale coherent vortical structures

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Book Series: Dissertationsreihe am Institut für Hydromechanik der Universität Karlsruhe (TH) ISSN: 14394111 ISBN: 3937300635 Year: Volume: 2005,2 Pages: XXVI, 398 p. DOI: 10.5445/KSP/1000003453 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: General and Civil Engineering
Added to DOAB on : 2019-07-30 20:01:59
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Shallow turbulent wake flows are generated by large obstacles - like islands or headlands - introduced to shallow turbulent open-channel flows. Large-scale quasi two-dimensional vortices may shed off from an obstacle, and advect downstream in a vertical shear flow with predominantly small-scale turbulence induced by bottom friction. Experimental, analytical, and numerical techniques are employed in the present study to characterize the mean flow and turbulence properties of shallow wakes; mechanisms of generation and decay of large-scale vortical structures are clarified, as is their influence on momentum and mass transport in shallow wakes; the global and local stability of shallow wakes is analyzed and evidenced from experimental data. Part I of this work covers non-intrusive optical measurement techniques especially adapted to investigate shallow shear flows. Flow velocities and mass concentrations are obtained (i) point-wise with high spatiotemporal resolution using a combinded LDV-LIF system, and (ii) field-wise using near-surface PIV and depth-averaged PCA systems with a coupling by phase-resolved averaging. Improved algorithms for the evaluation of mass concentrations are based on hydro-optical models of the underlying fluorescence and light attenuation processes. Part II addresses the time-mean description of shallow wake flows. The stochastic description of the turbulence fields displays a characteristic spectral distribution both of kinetic energy and of mass variance, which is partially consistent with the theory of unbounded 2D turbulence at large scales, and with the theory of homogeneous 3D turbulence at small scales. An integral wake model including the effect of bottom friction is derived analytically, and is validated by experimental data. The time-mean distributions of flow velocities and of mass concentration allow to identify wake near fields and far fields with specific asymptotic wake developments. Wake stability classes are associated with local stability regions suggested by linear stability analyses. Part III elaborates the structure and dynamics of quasi-periodic wake flows and the significance of large-scale eddies. This involves a structure identification scheme to educe individual vortices, and a phase-resolved averaging procedure to decompose the flow fields into large-scale coherent and small-scale turbulent parts. A Numerical Particle Tracking technique is employed to model the mass transport and to elucidate different diffusion and dispersion effects.

Numerische Simulation wirbeldynamischen Instabilitätsverhaltens turbulenter Vormischflammen

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ISBN: 9783731502661 Year: Pages: xxx, 317 p. DOI: 10.5445/KSP/1000043130 Language: GERMAN
Publisher: KIT Scientific Publishing
Subject: Chemical Engineering
Added to DOAB on : 2019-07-30 20:01:57
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This work contributes to an improved understanding of the driving mechanisms of the upstream propagation of turbulent premixed flames in enclosed vortex tubes within stationary gas turbine combustion systems. For this purpose, a Flamelet approach based on coupling a transport equation of the flame surface density with the description of laminar Flamelets to turbulent conditions is developed. This coupled approach enables the deduction of an explanation of this flashback phenomenon.

Computational Aerodynamic Modeling of Aerospace Vehicles

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ISBN: 9783038976103 Year: Pages: 294 DOI: 10.3390/books978-3-03897-611-0 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering --- Transportation
Added to DOAB on : 2019-03-08 11:42:05
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Currently, the use of computational fluid dynamics (CFD) solutions is considered as the state-of-the-art in the modeling of unsteady nonlinear flow physics and offers an early and improved understanding of air vehicle aerodynamics and stability and control characteristics. This Special Issue covers recent computational efforts on simulation of aerospace vehicles including fighter aircraft, rotorcraft, propeller driven vehicles, unmanned vehicle, projectiles, and air drop configurations. The complex flow physics of these configurations pose significant challenges in CFD modeling. Some of these challenges include prediction of vortical flows and shock waves, rapid maneuvering aircraft with fast moving control surfaces, and interactions between propellers and wing, fluid and structure, boundary layer and shock waves. Additional topic of interest in this Special Issue is the use of CFD tools in aircraft design and flight mechanics. The problem with these applications is the computational cost involved, particularly if this is viewed as a brute-force calculation of vehicle’s aerodynamics through its flight envelope. To make progress in routinely using of CFD in aircraft design, methods based on sampling, model updating and system identification should be considered.

Keywords

wake --- bluff body --- square cylinder --- DDES --- URANS --- turbulence model --- large eddy simulation --- Taylor–Green vortex --- numerical dissipation --- modified equation analysis --- truncation error --- MUSCL --- dynamic Smagorinsky subgrid-scale model --- kinetic energy dissipation --- computational fluid dynamics (CFD) --- microfluidics --- numerical methods --- gasdynamics --- shock-channel --- microelectromechanical systems (MEMS) --- discontinuous Galerkin finite element method (DG–FEM) --- fluid mechanics --- characteristics-based scheme --- multi-directional --- Riemann solver --- Godunov method --- bifurcation --- wind tunnel --- neural networks --- modeling --- unsteady aerodynamic characteristics --- high angles of attack --- hypersonic --- wake --- chemistry --- slender-body --- angle of attack --- detection --- after-body --- S-duct diffuser --- flow distortion --- flow control --- vortex generators --- aeroelasticity --- reduced-order model --- flutter --- wind gust responses --- computational fluid dynamics --- convolution integral --- sharp-edge gust --- reduced order aerodynamic model --- geometry --- meshing --- aerodynamics --- CPACS --- MDO --- VLM --- Euler --- CFD --- variable fidelity --- multi-fidelity --- aerodynamic performance --- formation --- VLM --- RANS --- hybrid reduced-order model --- quasi-analytical --- aeroelasticity --- flexible wings --- subsonic --- wing–propeller aerodynamic interaction --- p-factor --- installed propeller --- overset grid approach

Engineering Fluid Dynamics 2018

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ISBN: 9783039281121 9783039281138 Year: Pages: 256 DOI: 10.3390/books978-3-03928-113-8 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: General and Civil Engineering --- Technology (General)
Added to DOAB on : 2020-01-30 16:39:46
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“Engineering Fluid Dynamics 2018”. The topic of engineering fluid dynamics includes both experimental as well as computational studies. Of special interest were submissions from the fields of mechanical, chemical, marine, safety, and energy engineering. We welcomed both original research articles as well as review articles. After one year, 28 papers were submitted and 14 were accepted for publication. The average processing time was 37.91 days. The authors had the following geographical distribution: China (9); Korea (3); Spain (1); and India (1). Papers covered a wide range of topics, including analysis of fans, turbines, fires in tunnels, vortex generators, deep sea mining, as well as pumps.

Keywords

axial fan --- rotating stall --- aerodynamic noise --- numerical simulation --- noise spectrum --- centrifugal pump --- radiation noise --- distribution characteristic --- acoustic energy --- experimental research --- thermosyphon --- volume of fluid --- multiphase flow --- evaporation and condensation --- centrifugal pump --- impeller --- blade wrap angle --- blade exit angle --- optimized design --- deep sea mining --- manganese nodules exploitation --- hydraulic collecting --- suction flow field --- dimensional analysis --- circumferential groove casing treatment --- sweep and lean --- CGCT-blade integrated optimization --- computational fluid dynamics (CFD) --- flow around cylinder --- fluid structure interaction (FSI) --- hydrodynamic response --- numerical methods --- simulation and modeling --- vortex induced vibration (VIV) ratio --- gas turbine --- axial gap --- hot streak --- heat transfer --- leading edge --- global optimization --- cavitation inception --- orthogonal test --- CFD simulation --- two-stage axial fan --- numerical simulation --- abnormal blade installation angle --- rotating stall --- Tesla turbine --- fluid dynamics --- disc thickness --- disc spacing distance --- isentropic efficiency --- plug-holing --- tunnel slope --- fire --- natural ventilation --- ventilation performance --- aspect ratio --- evacuation --- fire propagation --- tunnel vehicle fire --- unsteady heat release rate --- flow control --- vortex generators --- source term --- Computational Fluid Dynamics (CFD) --- OpenFOAM --- wind tunnel

Modern Sample Preparation Approaches for Separation Science

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ISBN: 9783039214112 9783039214129 Year: Pages: 282 DOI: 10.3390/books978-3-03921-412-9 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Chemistry (General) --- Analytical Chemistry
Added to DOAB on : 2019-12-09 11:49:15
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This book will provide the most recent knowledge and advances in Sample Preparation Techniques for Separation Science. Everyone working in a laboratory must be familiar with the basis of these technologies, and they often involve elaborate and time-consuming procedures that can take up to 80% of the total analysis time. Sample preparation is an essential step in most of the analytical methods for environmental and biomedical analysis, since the target analytes are often not detected in their in-situ forms, or the results are distorted by interfering species. In the past decade, modern sample preparation techniques have aimed to comply with green analytical chemistry principles, leading to simplification, miniaturization, easy manipulation of the analytical devices, low costs, strong reduction or absence of toxic organic solvents, as well as low sample volume requirements.Modern Sample Preparation Approaches for Separation Science also provides an invaluable reference tool for analytical chemists in the chemical, biological, pharmaceutical, environmental, and forensic sciences.

Keywords

vitamins --- extraction --- determination --- review --- sample preparation --- matrix solid phase dispersion --- sorbent --- miniaturization --- on-line --- blueberry --- non-anthocyanin polyphenol --- vortex-assisted dispersive liquid-liquid microextraction --- response surface methodology --- desirability function approach --- nail --- curie temperature --- high-frequency heating --- liquid chromatography–tandem mass spectrometry --- caffeine --- amlodipine --- gas chromatography --- hydrogel --- hormones --- pectin --- polyvinyl alcohol --- sample preparation --- in-tube SPME --- UHPLC-MS/MS --- organic-based monoliths --- antipsychotics --- plasma samples --- schizophrenic’ patients --- salting-out assisted liquid–liquid extraction --- sugaring-out assisted liquid–liquid extraction --- hydrophobic-solvent assisted liquid–liquid extraction --- subzero-temperature assisted liquid–liquid extraction --- phenolic compounds --- sorbent-based techniques --- multi-spheres adsorptive micro-extraction (MSA?E) --- floating sampling technology --- caffeine and acetaminophen tracers --- environmental water matrices --- vortex-assisted dispersive liquid-liquid microextraction --- China herbal tea --- pesticides residue --- aflatoxins --- UPLC-MS/MS --- vortex-synchronized matrix solid-phase dispersion --- crab shells --- ionic liquids --- anthraquinones --- Cassiae Semen --- sample preparation --- nanocomposite --- pathogenic --- enrichment --- nucleic acid isolation --- sample preparation with TLC/HPTLC --- solvent front position extraction --- solvent delivery with a moving pipette --- automation --- LC–MS/MS --- environmental analysis --- whole water --- trace analysis --- SPE --- large volume --- in-line filter --- sand --- flow rate --- pharmaceuticals --- hormones --- pesticides --- space instrumentation --- liquid chromatography --- oligopeptides --- trapping system --- membrane-based microextraction --- barbiturates --- simultaneous determination --- whole blood --- urine --- liver --- sample preparation --- oxylipins --- protein precipitation --- liquid–liquid extraction --- solid-phase extraction --- biological samples --- chlorophenoxy acid herbicides --- HPLC --- hydrophobic in-tube solid-phase microextraction --- poly (OMA-co-TRIM) monolithic column --- rice grains --- gold --- sample preparation --- preconcentration --- geological samples

Wind Turbine Aerodynamics

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ISBN: 9783039215249 9783039215256 Year: Pages: 410 DOI: 10.3390/books978-3-03921-525-6 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering
Added to DOAB on : 2019-12-09 11:49:15
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Wind turbine aerodynamics is one of the central subjects of wind turbine technology. To reduce the levelized cost of energy (LCOE), the size of a single wind turbine has been increased to 12 MW at present, with further increases expected in the near future. Big wind turbines and their associated wind farms have many advantages but also challenges. The typical effects are mainly related to the increase in Reynolds number and blade flexibility. This Special Issue is a collection of 21 important research works addressing the aerodynamic challenges appearing in such developments. The 21 research papers cover a wide range of problems related to wind turbine aerodynamics, which includes atmospheric turbulent flow modeling, wind turbine flow modeling, wind turbine design, wind turbine control, wind farm flow modeling in complex terrain, wind turbine noise modeling, vertical axis wind turbine, and offshore wind energy. Readers from all over the globe are expected to greatly benefit from this Special Issue collection regarding their own work and the goal of enabling the technological development of new environmentally friendly and cost-effective wind energy systems in order to reach the target of 100% energy use from renewable sources, worldwide, by 2050

Keywords

H-type floating VAWT --- truss Spar floating foundation --- coupling of aerodynamics and hydrodynamics --- computational fluid dynamics --- wind farm --- complex terrain --- SCADA --- met mast measurements --- wind turbine --- simplified free vortex wake --- vortex ring --- aerodynamics --- axial steady condition --- variable pitch --- H-type VAWT --- straight blade --- DMST model --- NACA0012 --- wind energy --- power coefficient --- tip speed ratio --- wind turbine blade optimization --- computational fluid dynamic --- actuator disc --- wake effect --- Non-dominated Sorting Genetic Algorithm (NSGA-II) --- wind turbine airfoil --- dynamic stall --- boundary layer separation --- aerodynamic characteristics --- rotor blade optimization --- blade parametrization --- computational fluid dynamics --- OpenFOAM --- gradient-based --- adjoint approach --- wind turbine optimization --- low wind speed areas --- cost of energy --- particle swarm optimization --- dynamic stall --- pitch oscillation --- oscillating freestream --- rotational augmentation --- wind turbine --- turbulence --- super-statistics --- piezo-electric flow sensor --- ABL stability --- laminar-turbulent transition --- wind speed extrapolation --- atmospheric stability --- wind shear --- wind resource assessment --- wind turbine --- stall --- NREL Phase VI --- S809 airfoil --- MEXICO --- RANS --- wind turbine wakes --- turbulence --- actuator disk --- LES --- wind tunnel --- OpenFOAM --- wind turbine --- wind turbine design --- optimization --- blade length --- economic analysis --- typhoon --- wind turbine --- meso/microscale --- aerodynamic force --- mechanical performance --- thermography --- wind turbine blades --- defects --- image processing --- condition monitoring --- wind farm --- layout optimization --- design --- random search --- complex terrain --- airfoil design --- aerodynamic --- wind tunnel experiment --- VAWTs (Vertical axis wind turbines) --- computational fluid dynamics --- floating offshore wind turbine --- dynamic fluid body interaction --- semi-submersible platform --- OC5 DeepCWind --- wind turbine --- aerodynamics --- turbulent inflow --- Computational Fluid Dynamics --- blade element momentum theory --- actuator line method --- Fatigue Loads --- wind turbine noise source --- wind turbine noise propagation --- wind turbine wake --- n/a

Intermittency and Self-Organisation in Turbulence and Statistical Mechanics

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ISBN: 9783039211081 9783039211098 Year: Pages: 298 DOI: 10.3390/books978-3-03921-109-8 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Mathematics
Added to DOAB on : 2019-08-28 11:21:27
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There is overwhelming evidence, from laboratory experiments, observations, and computational studies, that coherent structures can cause intermittent transport, dramatically enhancing transport. A proper description of this intermittent phenomenon, however, is extremely difficult, requiring a new non-perturbative theory, such as statistical description. Furthermore, multi-scale interactions are responsible for inevitably complex dynamics in strongly non-equilibrium systems, a proper understanding of which remains a main challenge in classical physics. As a remarkable consequence of multi-scale interaction, a quasi-equilibrium state (the so-called self-organisation) can however be maintained. This special issue aims to present different theories of statistical mechanics to understand this challenging multiscale problem in turbulence. The 14 contributions to this Special issue focus on the various aspects of intermittency, coherent structures, self-organisation, bifurcation and nonlocality. Given the ubiquity of turbulence, the contributions cover a broad range of systems covering laboratory fluids (channel flow, the Von Kármán flow), plasmas (magnetic fusion), laser cavity, wind turbine, air flow around a high-speed train, solar wind and industrial application.

Multiscale Turbulent Transport

Authors: ---
ISBN: 9783039282128 9783039282135 Year: Pages: 210 DOI: 10.3390/books978-3-03928-213-5 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering
Added to DOAB on : 2020-04-07 23:07:08
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Turbulent transport is currently a prominent and ongoing investigation subject at the interface of methodologies from theory to numerical simulations and experiments, and it covers several spatiotemporal scales. Mathematical analysis, physical modelling, and engineering applications represent different facets of a classical, long-standing problem that is still far from being thoroughly comprehended. The goal of this Special Issue is to outline recent advances of such subjects as multiscale analysis in turbulent transport processes, Lagrangian and Eulerian descriptions of turbulence, advection of particles and fields in turbulent flows, ideal or nonideal turbulence (unstationary/inhomogeneous/anisotropic/compressible), turbulent flows in biofluid mechanics and magnetohydrodynamics, and the control and optimization of turbulent transport. The SI is open to regular articles, review papers focused on the state of the art and the progress made over the last few years, and new research trends.

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