1,721,457 research outputs found
Lucrezio milanese. Interpretazioni, letture, riscritture di Milo De Angelis e Giancarlo Pontiggia
No full textRilettura di Lucrezio nelle opere di Milo De Angelis e Giancarlo Pontiggia
Mathematical Models for the Assessment of an Environmental System in Landscape Ecology
Full text linkIn the framework of the theory of Landscape Ecology, a review of Lotka-Volterrra type models is proposed. Such models can be considered useful tools in order to represent and evaluate the dynamical behavior and the ecological stability of an environmental system which, as known, is subjected during time to several transformations. At this purpose, after such a review and presentation of different models, an application to an important wine region in France is performed using a model recently introduced in literature
Reduce Mould Risk during the Building Design Stage: Case Studies in Southeast China
Full text linkIndoor mould is usually discussed for the building operation phase rather than the
design stage. Moreover, the majority of existing studies were conducted by mechanical
engineers rather than architects, who typically have a broader view of the
whole project. The purpose of this paper is to obtain a quantitative mould risk scenario
across the Yangtze River Delta in China and make a matrix including all the
possible design chances to reduce the mould risk. A series of software is utilized to
simulate the mould risk in three main cities across that region. Simulation results confirm
high mould risk in all selected cities and the mould growth rates in different orientations
match the Wind-Driven-Rain diagram. After the simulation, all factors that
can be tuned for the mould prevention were analysed. Authors found that only
humidity and substrate (material of finishing layer) characteristics can be practically
controlled for the mould avoidance. Meanwhile, the Development Design Stage is
the essential design phase while the envelope is the most crucial building element
for mould prevention
Backward energy transfer and subgrid modeling approaches in wall-turbulence
No full textWe report here results from a Large Eddy Simulation (LES) of a turbulent channel flow at a friction Reynolds number Reτ = 550 performed with a new subgrid modeling approach proposed by the same authors in Cimarelli et al., Phys. Fluids, 26, 055103 (2014), [1]. This subgrid scale model aims at reproducing the double feature of energy sink and source of the small scales of wall flows which become relevant when large filter lengths are adopted. Here we report a further analysis of the model by considering the instantaneous behavior of events of backward and forward energy transfer
Analysis of turbulent Rayleigh-Bénard convection in the compound physical/scale space domain
No full textWe report the results from two distinct direct numerical simulations (DNS) of turbulent Rayleigh-Bénard convection (RBC) for Rayleigh number of 10^5 and Prandtl number of 0.7 in a laterally unbounded domain confined between two horizontal isothermal plates with no-slip and free-slip boundary conditions respectively. The central aim of the present work consists in a simultaneous description of both flows in a compound physical/scale space domain by using a generalized form of the classical Kolmogorov equation for the second-order velocity structure function. It has been found that the dynamics of the coherent structures in RBC, the so-called thermal plumes, are clearly reflected in the multi-scale energy budgets. In particular, the enlargement of thermal plumes following the impingement at the wall entails a transfer of scale-energy from small turbulent scales toward larger ones. This aspect shed light on the role of thermal plumes in turbulent RBC and could have a direct impact on future attempts to model the effects of small-scale motions in thermal convection
Analysis of the Yaglom equation and subgrid modelling approaches for thermally driven turbulence
No full textWe report a Direct Numerical Simulation (DNS) of turbulent Rayleigh-Bénard convection in a laterally unbounded domain confined between two horizontal parallel walls, for Rayleigh number 10^5 and Prandtl number 0.7. The DNS data are used to study the properties of the subgrid-scale flux of the active temperature field in the framework of Large Eddy Simulation (LES). In particular, starting from the generalized Yaglom equation, we analyse how the thermal energy is produced, transferred and dissipated in the augmented space of scales and positions of the flow. The understanding of these processes is then used to propose appropriate formulations for the subgrid-scale flux that will be tested by means of a posteriori analysis of LES simulations performed in the same flow conditions
Effect of Polymer Additives on Heat Transport in Turbulent Thermal Convection
No full textIn this Letter, we explore the possible effects of polymer additives on heat transport in turbulent thermal convective flows. Using both direct numerical simulations and shell-model calculations, we show that polymer additives can significantly enhance the heat transport in homogeneous turbulent thermal convection, which mimics the bulk of turbulent Rayleigh-Bénard convection. We also discuss the implication of our results for turbulent Rayleigh-Bénard convection, in which there are boundary layers in addition to the central bulk
Fighting energy poverty in a typical Peruvian rural house
Full text linkThis study evaluates a typical, informal construction in the Peruvian highlands of Cuzco, a site at an Equatorial latitude (13,5 degrees S), approximately, 3.400 mamsl, with a subtropical highland climate (Koppen Cwb). Its aim is to compare low-cost passive retrofit strategies, applicable in cities and rural areas with similar climate, and validate a best choice. To carry out this study a dynamic energy simulation was performed, using the typical meteorological year (IWEC) provided by ASHRAE. The model was used to understand the effects of simple changes in the envelope configuration and the associated effect on infiltration, and their combination, on the indoor comfort and the energy performance of the building. The outcomes were displayed in a simple Energy-needs/transformation cost chart and a Pareto curve was selected, identifying an optimal subset of solutions. Adequate indoor conditions can be obtained with the implementation of only passive strategies, mainly empowering the thermal insulation of walls, roofs and windows using simple, low cost, local technologies, and the control of the heat transmission toward the soil: the energy poverty of the informal settlements of Cuzco can be fought with very simple initiatives, that require investments with a reasonably short return of investment
Analysis of the Yaglom equation and subgrid modelling approaches for thermally driven turbulence
No full textWe report a Direct Numerical Simulation (DNS) of turbulent Rayleigh-Bénard convection in a laterally unbounded domain confined between two horizontal parallel walls, for Rayleigh number 105 and Prandtl number 0.7. The DNS data are used to study the properties of the subgrid-scale flux of the active temperature field in the framework of Large Eddy Simulation (LES). In particular, starting from the generalized Yaglom equation, we analyze how the thermal energy is produced, transferred and dissipated in the augmeneted space of scales and positions of the flow. The understanding of these processes is then used to propose appropriate formulations for the subgrid-scale flux that will be tested by means of a posteriori analysis of LES simulations performed in the same flow conditions
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