Experiments performed with bubbly flow in vertical pipes at different flow conditions covering the transition region: Simulation by coupling Eulerian, Lagrangian and 3D random walks models

[EN] Two phase flow experiments with different superficial velocities of gas and water were performed in a vertical upward isothermal cocurrent air-water flow column with conditions ranging from bubbly flow, with very low void fraction, to transition flow with some cap and slug bubbles and void fractions around 25%. The superficial velocities of the liquid and the gas phases were varied from 0.5 to 3 m/s and from 0 to 0.6 m/s, respectively. Also to check the effect of changing the surface tension on the previous experiments small amounts of 1-butanol were added to the water. These amounts range from 9 to 75 ppm and change the surface tension. This study is interesting because in real cases the surface tension of the water diminishes with temperature, and with this kind of experiments we can study indirectly the effect of changing the temperature on the void fraction distribution. The following axial and radial distributions were measured in all these experiments: void fraction, interfacial area concentration, interfacial velocity, Sauter mean diameter and turbulence intensity. The range of values of the gas superficial velocities in these experiments covered the range from bubbly flow to the transition to cap/slug flow. Also with transition flow conditions we distinguish two groups of bubbles in the experiments, the small spherical bubbles and the cap/slug bubbles. Special interest was devoted to the transition region from bubbly to cap/slug flow; the goal was to understand the physical phenomena that take place during this transition A set of numerical simulations of some of these experiments for bubbly flow conditions has been performed by coupling a Lagrangian code, that tracks the three dimensional motion of the individual bubbles in cylindrical coordinates inside the field of the carrier liquid, to an Eulerian model that computes the magnitudes of continuous phase and to a 3D random walk model that takes on account the fluctuation in the velocity field of the carrier fluid that are seen by the bubbles due to turbulence fluctuations. Also we have included in the model the deformation that suffers the bubble when it touches the wall and it is compressed by the forces that pushes it toward the wall, provoking that the bubble rebound like a ball.The authors of this paper are indebted to the National Plan of I+D by the support of the coordinated projects REMOD-ERN ENE2010-21368-C02-01/CON and ENE2010-21368-C02-02/CON to perform the experiments.Muñoz-Cobo, JL.; Chiva, S.; Ali Abdelaziz Essa, M.; Mendez, S. (2012). Experiments performed with bubbly flow in vertical pipes at different flow conditions covering the transition region: Simulation by coupling Eulerian, Lagrangian and 3D random walks models. Archives of Thermodynamics. 33(1):3-39. https://doi.org/10.2478/v10173-012-0001-4S33933

Mapping Genetic Diversity of Cherimoya (Annona cherimola Mill.): Application of Spatial Analysis for Conservation and Use of Plant Genetic Resources

There is a growing call for inventories that evaluate geographic patterns in diversity of plant genetic resources maintained on farm and in species' natural populations in order to enhance their use and conservation. Such evaluations are relevant for useful tropical and subtropical tree species, as many of these species are still undomesticated, or in incipient stages of domestication and local populations can offer yet-unknown traits of high value to further domestication. For many outcrossing species, such as most trees, inbreeding depression can be an issue, and genetic diversity is important to sustain local production. Diversity is also crucial for species to adapt to environmental changes. This paper explores the possibilities of incorporating molecular marker data into Geographic Information Systems (GIS) to allow visualization and better understanding of spatial patterns of genetic diversity as a key input to optimize conservation and use of plant genetic resources, based on a case study of cherimoya (Annona cherimola Mill.), a Neotropical fruit tree species. We present spatial analyses to (1) improve the understanding of spatial distribution of genetic diversity of cherimoya natural stands and cultivated trees in Ecuador, Bolivia and Peru based on microsatellite molecular markers (SSRs); and (2) formulate optimal conservation strategies by revealing priority areas for in situ conservation, and identifying existing diversity gaps in ex situ collections. We found high levels of allelic richness, locally common alleles and expected heterozygosity in cherimoya's putative centre of origin, southern Ecuador and northern Peru, whereas levels of diversity in southern Peru and especially in Bolivia were significantly lower. The application of GIS on a large microsatellite dataset allows a more detailed prioritization of areas for in situ conservation and targeted collection across the Andean distribution range of cherimoya than previous studies could do, i.e. at province and department level in Ecuador and Peru, respectively

Prehistoric remains of the sweet potato from the Casma valley of Peru

Volume: 49Start Page: 401End Page: 41

Early Complex Society on the North and Central Peruvian Coast: New Archaeological Discoveries and New Insights

Archaeological data from the north and central Peruvian coast are presented here as a means to explore key themes relating to social complexity, including complex society and its origins, newly resolved chronological issues, the relationship between iconography and society, and the definition of a new culture. Focusing on an early time span, from ca. 3000 to 200 cal BC, we identify key questions about the trajectory through which early Andean complexity developed, and we discuss new ideas about the chronological placement of Cerro Sechín and Chavín de Huántar. We also use an intertextual approach to study the iconography of the complex Sechín Alto polity and as a means to demonstrate duality, social hierarchy, and the origin of symbols within the society’s iconography. Finally, we highlight a newly described polity, centered in the Nepeña Valley, that is important because its urban traits presage later cultural complexity and because the recognition of this polity demonstrates the potential for similar discoveries of comparable small polities

Zastosowanie metody dużych wirów do przepływu turbulentnego w kanale i dyspersji cząstek

The Eulerian-Lagrangian approach has been applied to two-phase turbulent flows with dispersed heavy particles. First, numerical computations of the continuous phase (fluid) have been performed using the Direct Numerical Simulations (DNS) and Large-Eddy Simulations (LES) for the case of a fully-developed channel flow. Parallelisation efficiency of flow and particle solvers has been estimated. Residual turbulent kinetic energy has been found from filtered DNS (also called a priori LES); a model for this quantity has been assessed. Then, heavy particles have been tracked in the LES velocity field. Statistics of particle motion (mean velocity, intensity of velocity fluctuations) and the profile of cross-stream number density as well as preliminary results for particle wall deposition have been obtained.W pracy zastosowano podejście Eulera-Lagrange'a do wyznaczenia ruchu fazy dyspersyjnej (cząstki, krople) w turbulentnym przepływie dwufazowym. Obliczenia ruchu fazy ciągłej (płynu) przeprowadzono za pomocą rozwiązania pełnych równań przepływu (DNS) oraz przy użyciu metody dużych wirów (LES) dla przypadku rozwiniętego przepływu w kanale płaskim. Oszacowano efektywność zrównoleglenia obliczeń numerycznych. Określono poziom energii kinetycznej skal podsiatkowych; porównano ją z wynikami uzyskanymi z modelu dynamicznego. Wyznaczono trajektorie cząstek fazy dyspersyjnej w polu prędkości LES. Określono statystyki ich ruchu: prędkość średnią, intensywność fluktuacji prędkości, profil koncentracji cząstek w poprzek kanału; uzyskano wstępne wyniki dla separacji cząstek na ściankach