5 resultados para Reliable Theoretical Procedures
em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"
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Pós-graduação em Ciências da Motricidade - IBRC
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This paper presents a computational fluid dynamics (CFD) application about the axial fan design used in an agricultural spraying system with a theoretical and experimental analysis of comparative results between the characteristic curves of a fan for several rotations and numerical results for the influence of blade attack angle variation and optimization of the spraying system, both for a same rotation. Flow was considered three-dimensional, turbulent, isothermal, viscous and non-compressible in a steady state, disregarding any influence of the gravity field. The average turbulent field was obtained from the application of time average where the turbulence model required for closing the set of equations was the k-E model. Resolution of all connected phenomena was achieved with the help of a fluid dynamics computer, CFX, which uses the finite volumes technique as a numerical method. In order to validate the theoretical analysis, an experiment was conducted in a circular section of a horizontal wind tunnel, using a Pitot tube for pressure readings. The main results demonstrate that the methodology used, based on CFD techniques, is able to reproduce the phenomenological behavior of an axial fan in a spraying system because results were very reliable and similar to experimentally measured ones.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Lianas can change forest dynamics, slowing down forest regeneration after a perturbation. In these cases, it may be necessary to manage these woody climbers. Our aim was to simulate two management strategies: (1) focusing on abundant liana species and (2) focusing on the largest lianas, and contrast them with the random removal of lianas. We applied mathematical simulations for liana removal in three different vegetation types in southeastern Brazil: a Rainforest, a Seasonal Tropical Forest, and a Woodland Savanna. Using these samples, we performed simulations based on two liana removal procedures and compared them with random removal. We also used regression analysis with quasi-Poisson distribution to test whether larger lianas were aggressive, i.e., if they climbed into many trees. The procedure of cutting larger lianas was as effective as cutting them randomly and proved not to be a good method for liana management. Moreover, most of the lianas climbed into one or two trees, i.e., were not aggressive. Cutting the most abundant lianas proved to be a more effective method than cutting lianas randomly. This method could maintain liana richness and presumably should accelerate forest regeneration.