Search results for "FLOWS"

showing 10 items of 148 documents

Large eddy simulations on the effect of the irregular roughness shape on turbulent channel flows

2019

Abstract Large Eddy Simulations (LES) are carried out to investigate on the mean flow in turbulent channel flows over irregular rough surfaces. Here the attention is focused to selectively investigate on the effect induced by crests or cavities of the roughness. The irregular shape is generated through the super-imposition of sinusoidal functions having random amplitude and four different wave-lengths. The irregular roughness profile is reproduced along the spanwise direction in order to obtain a 2D rough shape. The analysis of the mean velocity profiles shows that roughness crests induce higher effect in the outer-region whereas roughness cavities cause the highest effects in the inner-reg…

Higher order statisticMaterials scienceTurbulence simulationTurbulent channel flows Large eddy simulation02 engineering and technologyReynolds stressSurface finish01 natural sciencesReynolds numberSettore ICAR/01 - Idraulica010305 fluids & plasmasPhysics::Fluid Dynamicssymbols.namesake0203 mechanical engineering0103 physical sciencesMean flowReynolds equationAnisotropyChannel flowFluid Flow and Transfer ProcessesTurbulenceMean velocity profileMechanical EngineeringIrregular roughneReynolds numberSinusoidal functionMechanicsCondensed Matter PhysicsOpen-channel flowShear stre020303 mechanical engineering & transportsAmplitudeReynolds streTurbulence Irregular shapeTurbulence intensityLESsymbolsTurbulence modulationInternational Journal of Heat and Fluid Flow
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X-ray Emission Mechanisms in Herbig - Haro objects .

2006

ISM: Herbig-Haro objects ISM: individual objects: HH 154 ISM: jets and outflows X-rays: ISM
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Il Paradigma della Città Fluida

2013

Nella recente crisi globale i poderosi flussi di capitali finanziari, sociali e relazionali che hanno alimentato la riqualificazione urbana nel corso degli ultimi quindici anni non sono più disponibili ad essere intercettati in maniera indiscriminata così come è stato possibile fino a qualche anno fa. Nell'era della crisi strutturale le città più dinamiche non sono più quelle in grado di attrarre progetti urbani iconici ed investitori spinti dal mercato immobiliare o dalla redditività delle attività ricreative, ma quelle città che, a partire dalle loro profonde e diversificate risorse culturali, saranno capaci di attuare una vera e propria “metamorfosi” per usarle come base per la creazione…

In current global crisis the strong flows of financial social and relational capitals that powered urban regeneration over the last fifteen years are no longer available to be tapped in an indiscriminate manner as was the case until just a few years ago. The most dynamic cities in the future will no longer be those that are able to attract urban projects and investors driven by the real estate market or leisure-based development but the cities that have deep and different cultural resources and that are able to use them as the basis for creating new urban cultures and for generating new economic values. Revitalising waterfront is no longer easy opportunity for long-term investments or for using the financial capital gains of corporation or hedge funds but a more creative-driven port city has to provide precious opportunities for real development – not only quantitative but more and more qualitative – that is able to produce effects in both the domain of collective assets and that of private capitals.Settore ICAR/21 - Urbanistica
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ASSESSMENT OF CORRUPTION EFFECT ON FOREIGN INVESTMENT FLOWS

2011

The purpose of the present paper is to investigate the impact of corruption on foreign direct investment (FDI) flows. Using data from the International Monetary Fund, Transparency International and United Nations conference about commerce and development data bases a cross-section econometric model was estimated to evaluate in which way and how strong corruption influence FDI inflows. Econometric modelling covers the period from year 2000 to 2007 and the data about 82 world countries that constitute more than 500 records. The main conclusion of the paper is that corruption has a negative and significant impact on the foreign direct investment inflows. Thus, changes in the level of corruptio…

Index (economics)Corruptionbusiness.industrymedia_common.quotation_subjectMonetary economicsInternational tradeForeign direct investmentEconometric modelcorruption; corruption perceptions index; cross-section; econometric model; FDI flowsTransparency (graphic)Per capitaCorruption Perceptions IndexEconomicsSingle pointbusinessmedia_commonLatgale National Economy Research
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The Highly Collimated Radio Jet of HH 80–81: Structure and Nonthermal Emission

2017

Radio emission from protostellar jets is usually dominated by free-free emission from thermal electrons. However, in some cases, it has been proposed that non-thermal emission could also be present. This additional contribution from non-thermal emission has been inferred through negative spectral indices at centimeter wavelengths in some regions of the radio jets. In the case of HH 80-81, one of the most powerful protostellar jets known, linearly polarized emission has also been detected, revealing that the non-thermal emission is of synchrotron nature from a population of relativistic particles in the jet. This result implies that an acceleration mechanism should be taking place in some pa…

JETS AND OUTFLOWS [ISM]Astrophysics::High Energy Astrophysical PhenomenaCiencias FísicasFOS: Physical sciencesAstrophysics::Cosmology and Extragalactic AstrophysicsAstrophysics01 natural sciencesCollimated lightACCELERATION OF PARTICLES//purl.org/becyt/ford/1 [https]FORMATION [STARS]0103 physical sciences010306 general physics010303 astronomy & astrophysicsSolar and Stellar Astrophysics (astro-ph.SR)Astrophysics::Galaxy AstrophysicsHigh Energy Astrophysical Phenomena (astro-ph.HE)PhysicsJet (fluid)Astronomy and Astrophysics//purl.org/becyt/ford/1.3 [https]Astrophysics - Astrophysics of GalaxiesAstronomíaAstrophysics - Solar and Stellar AstrophysicsSpace and Planetary ScienceAstrophysics of Galaxies (astro-ph.GA)Astrophysics - High Energy Astrophysical PhenomenaCIENCIAS NATURALES Y EXACTASThe Astrophysical Journal
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BVP ir skolinimo elgsena : empiriniai Baltijos šalių ekonomikos požymiai

2021

Darnus ekonominis vystymasis remiasi stabilia ir palankia verslo aplinka, kuri skatina organizacijų konkurencingumą. Komerciniai bankai palengvina kapitalo judėjimą iš mažiau efektyvių ekonomikos sektorių į labiau konkurencingas ekonomikos šakas. Šio tyrimo tikslas – išanalizuoti Baltijos šalių BVP dinamiką 2005-2010 metais ir patikrinti BVP koreliavimą su vietinių komercinių bankų išduotų paskolų verslui skaičiumi. Tyrimo rezultatai parodė, kad yra požymių, jog egzistuoja abipusė priklausomybė tarp BVP veiksnių ir išduotų paskolų, tai savo ruožtu sudaro pagrindą formuoti pasiūlymus, kaip gaivinti Baltijos šalių ekonomiką. Šešiose pramonės šakose atliktas Granger BVP ir skolinimo priežastin…

Kreditas. Paskolos / CreditEconomic sectorGDPGranger causality testBusiness environmentLietuva (Lithuania)EconomyGranger causalityBVPEconomicsGeneral Earth and Planetary SciencesCapital flowsGranger priežastingumo testasEmpirical evidenceGeneral Environmental ScienceRegional Formation and Development Studies
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Large eddy simulation of inertial particles dispersion in a turbulent gas-particle channel flow bounded by rough walls

2020

The purpose of this paper is to understand the capability and consistency of large eddy simulation (LES) in Eulerian–Lagrangian studies aimed at predicting inertial particle dispersion in turbulent wall-bounded flows, in the absence of ad hoc closure models in the Lagrangian equations of particle motion. The degree of improvement granted by LES models is object of debate, in terms of both accurate prediction of particle accumulation and local particle segregation; therefore, we assessed the accuracy in the prediction of the particle velocity statistics by comparison against direct numerical simulation (DNS) of a finer computational mesh, under both one-way and two-way coupling regimes. We p…

Lagrange multipliersLagrangian equationsParticle statisticsParticle statisticsVelocity controlComputational MechanicsDirect numerical simulationWall flow Accurate prediction02 engineering and technology01 natural sciencesReynolds numberSettore ICAR/01 - Idraulica010305 fluids & plasmasPhysics::Fluid Dynamicssymbols.namesake0203 mechanical engineeringEquations of motion0103 physical sciencesParticle velocityDispersionsPhysicsTurbulence modificationTurbulenceMechanical EngineeringLarge eddy simulationTwo phase flowReynolds numberMechanicsTurbulent wall-bounded flows Segregation (metallography)Open-channel flow020303 mechanical engineering & transportsParticle accumulationQuay wallssymbolsParticle segregationParticleForecastingParticle velocitiesLarge eddy simulationActa Mechanica
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Volatiles in pantellerite magmas: A case study of the Green Tuff Plinian eruption (Island of Pantelleria, Italy)

2013

Abstract The Green Tuff (GT) Plinian eruption, the largest in magnitude at Pantelleria, erupted 3 to 7 km3 DRE of pantellerite magma and a small volume of trachyte. Fifty-nine anorthoclase-hosted melt inclusions from the two basal pumice members were analyzed by FT-IR spectroscopy in order to assess the pre-eruptive H2O content in the pantellerite melt. Microanalytical methods were used to determine major element, Cl, F and S contents. Melt inclusions and glassy groundmasses have a nearly homogeneous pantelleritic composition (peralkaline index = 1.9-2.2) and variable water contents ranging from 1.4 to as high as 4.2 wt %, i.e. much higher than the 1.4 wt % of earlier published studies. The…

LavaSettore GEO/07 - Petrologia E PetrografiaGeochemistryTrachyteMagma chamberStrombolian eruptionGeophysicsEffusive eruptionGeochemistry and PetrologyPumiceMagmaThe Green Tuff (GT) Plinian eruption the largest in magnitude at Pantelleria erupted 3 to 7 km 3 DRE of pantellerite magma and a small volume of trachyte. Fifty-nine anorthoclase-hosted melt inclusions from the two basal pumice members were analyzed by FT-IR spectroscopy in order to assess the pre-eruptive H2Ocontent in the pantellerite melt. Microanalytical methods were used to determine major element Cl F and S contents. Melt inclusions and glassy groundmasses have a nearly homogeneous pantelleritic composition (peralkaline index = 1.9-2.2) and variable water contents ranging from 1.4 to as high as 4.2 wt % i.e. much higher than the 1.4 wt % of earlier published studies. The chlorine content is constant at about 1 wt %. Combined Cl and H2O data were used to estimate a confining pressure of about 50 MPa (depth around 2-3 km) for the GT magma chamber. The chamber was characterized by a compositional zoning with a dominant pantellerite overlying a trachyte magma. Soon after the GT eruption intra-caldera volcanism was dominated by the eruption of voluminous trachyte lavaflows while pantellerite melt production resumed after about 20 ka with numerous low-volume mildly explosive (Strombolian) to effusive eruptions. Comparison with data from the literature reveals that despite the differentexplosivity the post-caldera Strombolian eruptions and the GT Plinian eruption were fed by pantelleritic magmas with similar water contents. Chlorine and CO2contents suggest that the young magma reservoirs feeding the Strombolian to effusive activity were deeper (h≥4.5 km) than the much larger (based on erupted volumes) magma chamber which fed the GT eruptionGeologyMelt inclusionsJournal of Volcanology and Geothermal Research
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Particle transport in recirculated liquid metal flows

2008

PurposeAims to present recent activities in numerical modeling of turbulent transport processes in induction crucible furnace.Design/methodology/approach3D large eddy simulation (LES) method was applied for fluid flow modeling in a cylindrical container and transport of 30,000 particles was investigated with Lagrangian approach.FindingsParticle accumulation near the side crucible boundary is determined mainly by the ρp/ρ ratio and according to the presented results. Particle settling velocity is of the same order as characteristic melt flow velocity. Particle concentration homogenization time depends on the internal flow regime. Separate particle tracks introduce very intensive mass exchang…

Liquid metalMaterials scienceFurnacesDewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und MaschinenbauMechanical engineeringHomogenization (chemistry)ModellingPhysics::Fluid DynamicsSettlingRecirculated liquid metal flowsFluid dynamicsddc:510Electrical and Electronic EngineeringCrucible furnacesMelt flow indexTurbulent transport processesInternal flowTurbulenceApplied MathematicsLarge eddy simulationParticle physicsMechanicsComputer simulationDewey Decimal Classification::500 | Naturwissenschaften::510 | MathematikComputer Science ApplicationsComputational Theory and Mathematicsddc:620SimulationLiquid metalsNumerical analysisParticles (particulate matter)Large eddy simulationCOMPEL - The international journal for computation and mathematics in electrical and electronic engineering
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Instability of relativistic sheared jets and distinction between FRI and FRII sources

2002

We investigate the shear-driven instability of nonmagnetic relativistic jets with the bulk velocity, V , dependent on the cylindric radius, r. It is shown that instability can arise for any dependence of the velocity (or the Lorentz factor that is the same) on r. The shear-driven instability can e ectively operate in the whole volume of a jet. The growth time can be shorter than that of the Kelvin-Helmholtz instability. The considered instability leads to a turbulization of jets and can account for a distiction between the jets in the FRI and FRII sources. Urpin, V., Vadim.Urpin@uv.es

MHDAstrophysics::High Energy Astrophysical PhenomenaJets and outflowsAstrophysicsUNESCO::ASTRONOMÍA Y ASTROFÍSICAInstabilityMHD ; Instabilities ; ISM ; Jets and outflows ; Galaxiessymbols.namesakeAstrophysical jetComputer Science::DatabasesISMPhysicsJet (fluid)Astronomy and AstrophysicsRadiusGalaxies:ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia [UNESCO]Growth timeLorentz factorSpace and Planetary ScienceInstabilitiessymbolsBulk velocityUNESCO::ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogoniaMagnetohydrodynamics:ASTRONOMÍA Y ASTROFÍSICA [UNESCO]
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