1,720,983 research outputs found
An addition to the Sauli family's commissions in Bruges: the Genoa Annunciation Triptych attributed to Jan Provoost
No full textL’articolo indaga i 5 pannelli attribuiti a Jan Provoost, raffiguranti l’Annunciazione, San Pietro, Sant’Elisabetta d’Ungheria (Genova, Galleria di Palazzo Bianco), il Ritratto di Gentiluomo (Philadelphia, Museum of Art) e il Ritratto di Nobildonna (Madrid, Museo Thyssen-Bornemisza). Sulla base della ricerca storica e dell’indagini tecnica condotta sui pannelli e sull’underdrawing, viene provato che le 5 opere componevano in origine in trittico a scomparti mobili. Ulteriori indagini sulla sua storia di provenienza hanno portato a dimostra che esso si trovava in origine nell’Ospedale degli Incurabili di Genova e che fu commissionato da Antonio Sauli nel secondo decennio del Cinquecento. Alla luce di ciò, si discute infine il ruolo che Antonio , e suo fratello Vincenzo, cui si deve la committenza del Polittico della Cervara di Gerard David , ebbero nella diffusione della pittura fiamminga a Genova
Gli esordi di Federigo Alizeri, gostwriter di Francesco Pallavicino. L'Orazione sulla conservazione ed illustrazione dei patrii monumenti (Genova, 1839)
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Opere fiamminghe di Quattro e primo Cinquecento appartenute ad Alessandro Pallavicino Grimaldi: identificazione sulla base del catalogo di vendita del 1899
No full textOsservazioni sulla sperimentazione tecnica di Filippo Lippi tra quarto e quinto decennio del Quattrocento
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Numerical Simulation of Free Surface Flows With Heat and Mass Transfer
No full textThe paper presents CFD validation results for horizontal, stratified flows of sub-cooled water
with condensation of saturated dry steam along the water surface. These are important flow phenomena relevant for pressurized thermal shocks (PTS). The experimental data for assessing the accuracy of the CFD results have been obtained in the LAOKOON test facility of Technische
Universität München.
Computational results have been obtained with the NEPTUNE_CFD and ANSYS CFX CFD
codes. Co- and counter current flows with energy and mass transfer at the free surface have been simulated. The mathematical models used in the calculations are based on the Euler-Euler two-fluid model concept. The ANSYS CFX study investigated mainly the influence of two-phase flow model parameters, like interfacial length scales and interfacial heat transfer coefficients. The influence of using a homogeneous two-phase model versus a full two-fluid model was also
examined. The NEPTUNE_CFD calculations were run with more advanced models for the interfacial drag coefficient and interfacial energy transfer. For instance, the interfacial energy transfer
models were based on the surface renewal theory, and different approaches to calculate the interfacial area density were studied.
Both CFD codes showed qualitative agreement with the data, but tend to under-predict the temperature in the water layer which is an important quantity to assess the effects of PTS. Unfortunately the LAOKOON data are not very detailed regarding inlet and outlet boundary condition,
which makes a more thorough investigation of the discrepancies between predictions and data
difficult
CFD Code Validation and Benchmarking Against Stratified Air-Water Flow Experimental Data
No full textPressurized thermal shock (PTS) modelling has been identified as one of the most important industrial needs related to nuclear
reactor safety. A severe PTS scenario limiting the reactor pressure vessel (RPV) lifetime is the cold water emergency core cooling
(ECC) injection into the cold leg during a loss of coolant accident (LOCA). Since it represents a big challenge for numerical
simulations, this scenario was selected within the European Platform for Nuclear Reactor Simulations (NURESIM) Integrated
Project as a reference two-phase problem for computational fluid dynamics (CFDs) code validation. This paper presents a CFD
analysis of a stratified air-water flow experimental investigation performed at the Institut de M ́ecanique des Fluides de Toulouse
in 1985, which shares some common physical features with the ECC injection in PWR cold leg. Numerical simulations have
been carried out with two commercial codes (Fluent and Ansys CFX), and a research code (NEPTUNE CFD). The aim of this
work, carried out at the University of Pisa within the NURESIM IP, is to validate the free surface flow model implemented in
the codes against experimental data, and to perform code-to-code benchmarking. Obtained results suggest the relevance of threedimensional
effects and stress the importance of a suitable interface drag modelling
Impinging jet studies for turbulent modelling assessment and code benchmarking
No full textPressurized Thermal Shock has been identified as one of the most important industria! needs related to nuc!ear reactor safety. A very severe PTS scenario, generating phenomena of Jet Impingement with heat transfer, is the cold water Emergency Core Cooling injection into the cold leg during a LOCA. Numerica! simulations of the PTS phenomena through Computational Fluid Dynamics codes could supply accurate predictions of the thermal load, but it is necessary to verify and validate the applicability ofthese codes in relevant demonstration test-cases. The impinging jet flow represents a particularly challenging case for the validation ofturbulence models. This work presents the study of a sing!e-phase axisymmetric turbulentjet impinging orthogona!!y on a surface, with heat transfer. The problern have been analyzed with two commercia! CFD codes, FLUENT and Ansys CFX, adopting different turbulence models, near wa!1 treatment and mesh refinement in the wall region. Numerica! results have been compared with cxperimcntal data available in the ERCOFTAC database. The numerica! predictions indicate that k — e mode!s generally !ead to far too !arge levels ofturbulence near the stagnatibn point. This exeessive energy in turn induees too much high heat transfer coefficients and turbu!ent mixing with ambient fluid
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