Search results for " Drag"
showing 10 items of 43 documents
UAQ4 Levitating Train: Italian Maglev Transportation System
2014
This article illustrates the University of L'Aquila model 4 (UAQ4) Italian maglev train, a transportation system with zero motion resistance (except aerodynamic drag) and greatly reduced energy consumption, approaching zero at a low constant speed. The project is the result of more than 40 years of research in the field of nonconventional highspeed transportation systems. Its technological feasibility has been tested in the laboratory at the University of L'Aquila, Italy.
CFD simulations of dense solid–liquid suspensions in baffled stirred tanks: Prediction of solid particle distribution
2013
Abstract Industrial tanks devoted to the mixing of solid particles into liquids are often operated at an impeller speed N less than Njs (defined as the lowest speed allowing the suspension of all particles): under such conditions the distribution of solid-particles is very far from being homogeneous and very significant concentration gradients exist. The present work is devoted to assessing the capability of Computational Fluid Dynamics (CFD) in predicting the particle distribution throughout the tank. The CFD model proposed by Tamburini et al. [58] and successfully applied to the prediction of the sediment amount and shape was adopted here to simulate the particle distribution under partia…
On the induced drag reduction due to propeller-wing interaction
1995
AbstractThe aerodynamic interaction between a wing and a couple of propellers in tractor configuration is investigated by means of a model based on the lifting line concept and under the assumption of quasi-steady incompressible motion of inviscid fluid. The ways the propellers influence the wing performances, particularly the induced drag, are analysed. It turns out that the lift increase and the possible drag reduction depend strongly on the direction of the blade rotation and on the propeller distances from midspan, and result from two main effects: the direct propeller induction on the wing and the modification of the lift distribution along the span. An additional nonlinear (mixed) con…
L’origine dei feudi nei Regni di Napoli e Sicilia nell’opera di Giacinto Dragonetti
2016
The article focuses on Giacinto Dragonetti’s Origins of the Fiefs in the Neapolitan and Sicilian Kingdom. The book was published in 1788 as expression of the governmental policy concerning the good interpretation of the Volentes chapter and the right exerted by the fiscal system on the fiefs without heirs. Through a detailed analysis of the text and the context into which it was written, the article aims to deepen the knowledge of the cultural changes caused by the intertwining among historiography, politics and law into the framework of the discussions relating the feudal matter in the second half of the Eighteenth century. Paying particular attention to the epistemological and methodologi…
Alla ricerca della sicurezza e della qualità: il modello di miglioramento dell'Oncologia Medica nel Policlinico Universitario di Palermo
2015
[In search of safety and quality: the improvement model proposed by the Oncology Department of the Palermo University] Over the past 20 years the field of oncology has product therapeutic innovations that have radically changed the prognosis of the most prevalent malignancies, since introduction of so-called targeted molecular agents. As a result of these changes, also the management of cancer patients has become more complex requiring technologies and skills that involve many professionals (medical oncologists, biologists, molecular geneticists, surgeons, pathologists, radiologists, nurses and psychologists), each engaged in a different stage of the disease, with the common goal of ensurin…
Dense Solid-Liquid Off-Bottom Suspension Dynamics: Simulation and Experiment
2009
Dense solid-liquid off-bottom suspension inside a baffled mechanically agitated stirred tank equipped with a standard Rushton turbine is investigated. Dynamic evolution of the suspension from start up to steady state conditions has been inspected by both visual experiments and computational fluid dynamics. A classical Eulerian-Eulerian Multi Fluid Model along with the “homogeneous” k-epsilon turbulence model is adopted to simulate suspension dynamics. In these systems the drag inter-phase force affects both solids suspension and distribution. Therefore, different computational approaches are tested in order to compute this term. Simulation results are compared with images acquired on the re…
The effect of the slope of irregularly distributed roughness elements on turbulent wall-bounded flows
2008
Wall roughness produces a downward shift of the mean streamwise velocity profile in the log region, known as the roughness function. The dependence of the roughness function on the height and arrangement of roughness elements has been confirmed in several studies where regular rough walls were analysed; less attention has been paid to non-regular rough walls. Here, a numerical analysis of turbulent flows over irregularly shaped rough walls is performed, clearly identifying the importance of a parameter, called the effective slope (ES) of the wall corrugations, in characterizing the geometry of non-smooth irregular walls. The effective slope proves to be one of the fundamental geometric para…
Breve explicación de los puntos mas esenciales de las Reales Ordenanzas que los caballeros cadetes del Regimiento de Dragones de Villaviciosa harán e…
Port. amb orla tip Fris, vinyeta, caplletra ornada i altra ornamentació Text a 1 col. - Reclams Sign.: [ ]2, A16