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Phytoplankton production modelling in three marine ecosystems—static versus dynamic approach

Macedo, M.F.; Duarte, Pedro
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2006 ENG
Relevância na Pesquisa
46.1%
Phytoplankton productivity is usually determined from water samples incubated at a number of irradiance levels during several hours. The resultant productivity-irradiance (P–E) curves are then used to estimate local and/or global phytoplankton production. However, there is growing evidence that these curves, referred as static, underestimate phytoplankton photosynthesis to a great deal, by assuming a stable response to light over the incubation period. One of the drawbacks of static P–E curves is the overestimation of photoinhibition. In this work, three one-dimensional vertically resolved models were developed as simply as possible, to investigate differences between static and dynamic phytoplankton productivity in three marine ecosystems: a turbid estuary, a coastal area and an open ocean ecosystem. The results show that, when photoinhibition development time is considered (dynamic model), the primary production estimates are always higher than when calculated with the static model. The quantitative importance of these differences varies with the type of ecosystem and it appears to be more important in coastal areas and estuaries (from 21 to 72%) than in oceanic waters (10%). Thus, these results suggest that primary production estimates...

A Stochastic Dynamic Methodology (SDM) to the modelling of trophic interactions, with a focus on estuarine eutrophication scenarios

Silva-Santos, Pedro; Pardal, Miguel Ângelo; Lopes, Ricardo Jorge; Múrias, Tiago; Cabral, João Alexandre
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Artigo de Revista Científica Formato: aplication/PDF
ENG
Relevância na Pesquisa
46.1%
In the face of global change, declines in environmental quality are of increasing concern, especially in shallow coastal areas, densely populated and commonly affected by nutrient enrichment. The warm temperate Mondego estuary (Western Portugal), in common with many other shallow estuarine areas, is exhibiting increased macroalgal growth due to nutrient enrichment. The increase of macroalgal biomass and possible shift of other primary producers resulting from eutrophication, may have profound effects on estuarine trophic chain. The present paper examined the performance of a holistic Stochastic Dynamic Methodology (SDM) in predicting the tendencies of three representative trophic levels as a response to the increase of nutrient concentrations. Therefore, the proposed methodology has been developed by focusing on the interactions between conceptually isolated key-components, such as primary producers (macroalgae and seagrass), some relevant benthic macroinvertebrates, wading birds and changes in local physicochemical conditions. The dynamic model developed was preceded by a conventional multivariate statistical procedure (stepwise multiple regression analysis) performed to discriminate the significant relationships between prevailing biological and environmental variables. Since this statistical analysis is static...

Política de operação preditiva estabilizada via termo inercial utilizando "analytic signal", "dynamic modelling" e sistemas inteligentes na previsão de vazões afluentes em sistemas hidrotérmicos de potência; Predictive operation policy stabilized via inertial term using analytic signal, dynamic modelling and intelligent systems on hydrothermal power systems

Sacchi, Rodrigo
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 08/06/2009 PT
Relevância na Pesquisa
66.33%
Este trabalho de pesquisa objetivou a obtenção de uma nova política de operação que melhor caracterizasse o comportamento ótimo dos sistemas hidrelétricos de potência, mesmo diante das mais variadas condições hidrológicas. Este trabalho teve duas linhas de investigação. Uma tratou do problema de previsão de vazões afluentes mensais, na busca por abordagens e técnicas que definissem bons modelos de previsão. A outra linha de pesquisa tratou de encontrar uma nova política de operação, para o problema de planejamento da operação, que fosse capaz de definir uma seqüência de decisões operativas mais estáveis, confiáveis e de menor custo operativo. Na primeira linha de pesquisa, investigou-se três aspectos importantes na definição de um modelo de previsão: técnicas de pré-processamento dos dados, definição automática do espaço de entrada e avaliação do desempenho de alguns modelos de redes neurais e sistemas Fuzzy como modelos de previsão. Nestes aspectos foram investigadas a utilização da análise dos componentes principais e o tratamento da série temporal de vazões afluentes como um sinal discreto, utilizando-se a representação "analytic signal". Para a definição do espaço de entrada de maneira automática utilizou-se a abordagem da "dynamic modelling"...

A planar flexible robotic manipulator

Gamarra-Rosado, V. O.
Fonte: Mcb Univ Press Ltd Publicador: Mcb Univ Press Ltd
Tipo: Artigo de Revista Científica Formato: 787-796
ENG
Relevância na Pesquisa
46.1%
Presents the dynamic modelling of a flexible robotic manipulator with two flexible links and two revolute joints, which rotates in the horizontal plane. The dynamic equations are derived using the Newton-Euler formulation and the finite element method, based on elementary beam theory, which is used to discretize the displacements such that the small motion is represented in terms of nodal displacements. Computer simulation results are presented to illustrate this study. The dynamic model becomes necessary for use in future design and control applications.

Integration of proteomic data for predicting dynamic behaviour in an E. coli central carbon network after genetic perturbations

Costa, Rafael S.; Machado, C. D.; Rocha, I.; Ferreira, E. C.
Fonte: Universidade do Minho. Departamento de Engenharia Biológica Publicador: Universidade do Minho. Departamento de Engenharia Biológica
Tipo: Conferência ou Objeto de Conferência
Publicado em //2009 ENG
Relevância na Pesquisa
46.26%
One of the great challenges in the post‐genomic era is to understand the dynamic behaviour of a living cell. For that purpose, quantitative models describing metabolic network dynamics are a powerful tool as “dry lab” platforms to simulate experiments before they are performed in vivo. Kinetic models and stoichiometric genome scale models of the microbial metabolism are usually the two large‐scale modelling approaches most used. So far, few large scale kinetic models have been successfully constructed. The main reasons for this are not only the associated mathematical complexity, but also the large number of unknown kinetic parameters required in the rate equations to define the system. In contrast to kinetic models, the genome scale modelling approach bypasses these difficulties by using basically only stoichiometric information with certain physicochemical constraints to limit the space of a network without large fitted parameters sets. Although these constraint‐based models are highly relevant to predict a feasible set of steady‐state fluxes under a diverse range of genetic conditions, the steady‐state assumption may oversimplify cellular behaviour and cannot offer information about time dependent changes. To overcome these problems...

A new stochastic dynamic tool to improve the accuracy of mortality

Bastos, Rita; Santos, Mário; Cabral, João Alexandre
Fonte: Universidade de Trás-os-Montes e Alto Douro Publicador: Universidade de Trás-os-Montes e Alto Douro
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.21%
Although generally considered environmentally friendly, wind power has been associated with extensive mortality of birds and bats. In this perspective, there is a need for reliable estimates of fatalities at wind farms, where the heterogeneity of the basic information, used among environmental assessment studies, is unlikely to support an accurate universal estimation method. We tested the applicability of the Stochastic Dynamic Methodology (StDM) to estimate bat fatalities, based on multifactorial cause–effect relationships (by integrating multi-model inference statistical analysis and dynamic modelling) between mortality estimates, detected fatalities and the selected key-components of the reality, such as the real number of bat mortalities simulated, the rate of carcasses removal, the searcher efficiency, the monitoring periodicity and the number of turbines for different realistic scenarios associated with particular wind farm conditions. Although some existing mortality estimators are considered accurate, the choice of a given universal formula for all mortality assessments, based on deterministic parameters and assumptions, may originate unsuspected errors. Therefore, we propose a flexible dynamic modelling framework...

Testing a novel spatially-explicit dynamic modelling approach in the scope of the laurel forest management for the endangered Azores bullfinch (Pyrrhula murina) conservation.

Fonte: Universidade de Trás-os-Montes e Alto Douro Publicador: Universidade de Trás-os-Montes e Alto Douro
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.23%
The Azores bullfinch (Pyrrhula murina) is an endemic bird of São Miguel island (Azores Archipelago, Portugal), currently threatened by two of the major causes of biodiversity loss worldwide: invasion of native habitats by exotic plants and habitat destruction by land use changes. The aim of this research was to develop and test a novel spatially explicit modelling framework that predicts the Azores bullfinch responses to alternative realistic scenarios of native forest management. This was done by integrating Multi-Model Inference statistical analysis, Stochastic-Dynamic Modelling and Geographic Information Systems under a common framework relating bird population trends to changes in the surrounding habitats. Overall, in the next 25 years, the Azores bullfinch breeding population was predicted to increase around 19% as a consequence of habitat management actions already implemented (‘‘LIFE Priolo’’ project) or around 27% in the context of realistic future habitat restoration scenarios. These results represent, respectively, a supplementary increase of more 6% or more 13% in the Azores bullfinch abundance when compared with the trends simulated for the scenario without management. Nevertheless, those actions seemed to be relatively ineffective in promoting the expansion of the species from the actual restricted favourable area...

Performance of a stochastic-dynamic modelling methodology for running waters ecological assessment.

Cabecinha, Edna; Cortes, Rui; Cabral, João Alexandre
Fonte: Universidade de Trás-os-Montes e Alto Douro Publicador: Universidade de Trás-os-Montes e Alto Douro
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.18%
An holistic stochastic-dynamic modelling methodology has been developed in order to predict the ecological status of lotic systems in Northeast Portugal. These procedures focus on the interactions between conceptually isolated key-components, such as some relevant benthic macroinvertebrate metrics and changes in local habitat conditions. The proposed model was preceded by a conventional multivariate statistical treatment performed to discriminate the significant relationships between prevailing biological and environmental variables. Since this statistical analysis is static, the dataset recorded from the field included true gradients of habitat changes. In this way, the factors time and space are implicit in the respective treatment. Such a procedure gives credibility to the parameters included in the dynamic model construction. In order to enhance the importance of monitoring in aquatic systems based on ecological integrity indicators, different biotic metrics were selected from the studied benthic macroinvertebrate communities. The samples of aquatic macroinvertebrate, environmental and physical-chemical data were collected from three watersheds of mountain rivers in Northeast Portugal, between 1983 and 1985. The model validation was based on independent data from another watershed not included in the model construction. Thereafter...

Applying a stochastic-dynamic methodology (StDM) to facilitate ecological monitoring of running waters, using selected trophic and taxonomic metrics as state variables.

Cabecinha, Edna; Silva-Santos, Pedro; Cortes, Rui; Cabral, João Alexandre
Fonte: Universidade de Trás-os-Montes e Alto Douro Publicador: Universidade de Trás-os-Montes e Alto Douro
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.13%
As an improvement of a previous work [Cabecinha, E., Cortes, R., Cabral, J.A., 2004. Performance of a stochastic-dynamic modelling methodology for running waters ecological assessment. Ecol. Modell. 175, 303–317], the present paper examined the applicability of a holistic stochastic-dynamic methodology (StDM) in predicting the tendencies of benthic macroinvertebrate metrics from mountain streams facing expected scenarios either: (1) of pollution increase due to the agricultural intensification; or (2) of farming activity abandonment becoming less pollutant as a non-point source. The StDM is a sequential modelling process developed in order to predict the ecological status of changed ecosystems, from which management strategies can be designed. These procedures focus on the interactions between conceptually isolated key-components, such as some relevant trophic and taxonomic metrics and changes in local environmental conditions. The dataset recorded from the field included true gradients of environmental changes. The samples of aquatic macroinvertebrate, environmental and physical–chemical data were collected from four watersheds of mountain rivers in Northeast Portugal, between 1983 and 1985. The dynamic model developed was preceded by a conventional multivariate statistical procedure performed to discriminate the significant relationships between the selected components of the studied watersheds. The model validation was based on independent data from a watershed not included in the model construction. Overall...

A Stochastic Dynamic Methodology (SDM) to the modelling of trophic interactions, with a focus on estuarine eutrophication scenarios.

Silva-Santos, Pedro; Pardal, Miguel Ângelo; Lopes, Ricardo Jorge; Múrias, Tiago; Cabral, João Alexandre
Fonte: Universidade de Trás-os-Montes e Alto Douro Publicador: Universidade de Trás-os-Montes e Alto Douro
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.1%
In the face of global change, declines in environmental quality are of increasing concern, especially in shallow coastal areas, densely populated and commonly affected by nutrient enrichment. The warm temperate Mondego estuary (Western Portugal), in commonwithmanyothershallowestuarineareas, isexhibitingincreasedmacroalgalgrowthdue tonutrientenrichment.The increase of macroalgal biomass and possible shift of other primary producers resulting from eutrophication, may have profound effects on estuarine trophic chain. The present paper examined the performance of a holistic Stochastic Dynamic Methodology (SDM) in predicting the tendencies of three representative trophic levels as a response to the increase of nutrient concentrations.Therefore, the proposed methodology has been developed by focusing on the interactions between conceptually isolated key-components, such as primary producers (macroalgae and seagrass), some relevant benthic macroinvertebrates, wading birds and changes in local physicochemical conditions. The dynamic model developed was preceded by a conventional multivariate statistical procedure (stepwise multiple regression analysis) performed to discriminate the significant relationships between prevailing biological and environmental variables. Since this statistical analysis is static...

Simulating the ecological status of changed ecosystems by holistic applications of a new Stochastic-Dynamic Methodology (StDM). Chapter 4.

Cabral, João Alexandre; Cabecinha, Edna; Santos, Mário; Travassos, Paulo; Silva-Santos, Pedro
Fonte: Alonso M. S. and Rubio I. M. (Eds) Publicador: Alonso M. S. and Rubio I. M. (Eds)
Tipo: Parte de Livro
ENG
Relevância na Pesquisa
46.23%
A new Stochastic Dynamic Methodology (StDM) has been developed as a mechanistic understanding of the holistic ecological processes, by using appropriate statistical and dynamic modelling techniques. Our own recent research is based on the premise that the general statistical patterns of ecological phenomena are emergent indicia of complex ecological processes that do indeed reflect the operation of universal law-like mechanisms. This is the heart of the philosophy of the StDM, a sequential modelling process developed in order to predict the ecological status of changed ecosystems, taking into account stochastic/random phenomena that characterize the real ecological processes. The context of StDM, as we use in this chapter, refers to the application or final use of management models in the scope of programs to measure and monitor ecological integrity. The chapter describes briefly the theory and procedures of StDM, including modelling fundamentals and background statistical methods. It provides a demonstration how StDM can be used to build simple models and will assist the reader and guide the reading process through the examples of holistic ecological applications. In fact, the StDM was successfully tested in several types of ecosystems...

Dynamic modelling of induction machines.

Gol, Ozdemir
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //1993
Relevância na Pesquisa
46.29%
A great deal of attention has been paid to the modelling of induction machines under both steady state and dynamic operating conditions. Several different approaches adopted in formulating models include field modellíng, based on the evaluation of the magnetic field within the machine space, and the circuit modelling, which uses lumped parameters. This thesis compares various different modelling approaches, and postulates that judiciously formed circuit models can be used in predicting, with acceptable accuracy, the performance of an induction machine under different operating conditions. Two approaches are developed in detail, both of which share a common starting point, namely the airgap magnetomotive force set up by a single energised coil. In the first approach, the magnetomotive force distribution is evaluated in terms of space harmonics, leading to the formation of high order harmonic circuit models. The inclusion in the models of such phenomena as saturation, current displacement and core losses dramatically improves the prediction accuracy, which justifies their being labelled as high fidelity harmonic circuit models. They are particularly suitable in evaluating any parasitic behaviour under quasi dynamic operating conditions. The effects on the machine behaviour of a non-sinusoidat supply are accounted for by means of an aggregate time-harmonic supply model. In contrast...

Dynamic modelling of an electromechanical valve using frequency response data

Miller, R. L.; Smith, D. L.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Relatório
EN_US
Relevância na Pesquisa
46.19%
Dynamic modelling of electromechanical parts is often accomplished by conducting an analysis from first physical principles. While this is always a useful effort for physical insight, it may lead to transfer function models which are unnecessarily complex. This paper presents a supplementary dynamic modelling method based on frequency response data. The method is applied to modelling of a globe valve use for water flow control

Estratégias de modelagem dinâmica e simulação computacional do motor de indução trifásico.; Strategies of dynamic modelling and computational simulation of the three-phase induction motor.

Cad, Marcelo Machado
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 07/08/2000 PT
Relevância na Pesquisa
46.16%
Nesse trabalho procede-se a modelagem e simulação do motor de indução trifásico considerando-se as notações trifásicas, ortogonais, vetoriais e complexas, mos-trando seus equacionamentos e também o resultado das simulações. Para a simulação foram usados alguns programas de domínio da área acadêmica, comparando seus desempenhos quanto à apresentação de resultados e também tempo de processamen-to. Este trabalho apresenta também, um enfoque para o método de simulação do mo-tor de indução trifásico utilizando a notação vetorial complexa, o qual é baseado na notação vetorial do motor de indução que é caracterizado por grandezas complexas. Essa técnica é obtida através de simples manipulações das equações vetoriais do modelo do motor de indução compondo uma equação de estado complexa. Com o auxílio do programa Matlab, consegue-se simular o motor de indução trifásico sem a necessidade de separar os termos complexos em duas equações reais, relativas as partes real e imaginária. O que além de simplificar o procedimento de simulação também contribui para a construção do diagrama de blocos para poder entender melhor o comportamento do modelo estudado. São apresentadas no final do trabalho...

Modelagem de sistemas dinamicos atraves da sintese modal de componentes; System's dynamic modelling through of component modal synthesis

Cleudmar Amaral de Araujo
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 20/03/1998 PT
Relevância na Pesquisa
56.14%
Uma das principais técnicas de modelagem mixta de sistemas complexos ou de grande porte é a técnica de síntese modal. Os vários métodos de síntese modal propostos são formulados sob dois pontos de vista distintos, ou seja, considerando-se o sistema sem amortecimento ou com amortecimento geral. Além disso, surgem inerentes dificuldades na aplicação da metodologia de síntese modal na análise experimental. Neste trabalho é proposto uma técnica de síntese modal generalizada aplicada em sistemas sem amortecimento ou com amortecimento geral. O método utiliza um superconjunto modal de flexibilidade residual, cuja principal aplicação é na síntese modal experimental. O método utiliza um processo de remontagem das subestruturas que otimiza as equações finais da síntese. Propõe-se, também, um novo procedimento, definido como critério de eliminação automática de modos (CEA), que define um índice de qualidade para os modos das subestruturas, indicando quais serão aqueles mais apropriados para serem mantidos nas bases modais. Todas as metodologias propostas no trabalho foram implementadas em um software denominado Programa STRUCT. O método foi testado através de quatro exemplos de simulação. Foi feita uma validação experimental através de uma estrutura construída em escala reduzida...

Modelação Dinâmica de Sistemas de Drenagem Urbana. Aplicação a um caso de estudo

Ferreira, Paulo César Morgado
Fonte: Instituto Politécnico do Porto Publicador: Instituto Politécnico do Porto
Tipo: Dissertação de Mestrado
Publicado em //2014 POR
Relevância na Pesquisa
46.22%
A crescente expansão urbana e o incremento das exigências ambientais e financeiras promovem a implementação de abordagens sustentáveis para a gestão das infraestruturas sanitárias. Assim, o recurso a instrumentos de monitorização e à modelação matemática surge como o caminho para a racionalização do investimento e a otimização dos sistemas existentes. Neste contexto, a modelação dinâmica de sistemas de drenagem urbana assume relevância para o controlo e redução dos caudais em excesso e das descargas de poluentes nos meios recetores, resultantes de um incremento significativo de afluências pluviais indevidas, de problemas de sub-dimensionamento ou falta de operação e manutenção. O objetivo da presente dissertação consiste na modelação, calibração e diagnóstico do sistema intercetor de Lordelo utilizando o software Storm Water Management Model, através dos dados recolhidos a partir do projeto de Reabilitação dos intercetores de Lordelo, elaborado pela Noraqua. A modelação considera a avaliação das afluências de tempo seco e as afluências pluviais pelo software Sanitary Sewer Overflow Analysis and Planning Toolbox. Com efeito, a simulação dinâmica, permitiu um conhecimento mais detalhado do sistema...

Dynamic Modelling and Adaptive Traction Control for Mobile Robots

Albagul, A.; Wahyudi
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 08/11/2004
Relevância na Pesquisa
46.1%
Mobile robots have received a great deal of research in recent years. A significant amount of research has been published in many aspects related to mobile robots. Most of the research is devoted to design and develop some control techniques for robot motion and path planning. A large number of researchers have used kinematic models to develop motion control strategy for mobile robots. Their argument and assumption that these models are valid if the robot has low speed, low acceleration and light load. However, dynamic modelling of mobile robots is very important as they are designed to travel at higher speed and perform heavy duty work. This paper presents and discusses a new approach to develop a dynamic model and control strategy for wheeled mobile robot which I modelled as a rigid body that roles on two wheels and a castor. The motion control strategy consists of two levels. The first level is dealing with the dynamic of the system and denoted as Low level controller. The second level is developed to take care of path planning and trajectory generation.

Dynamic Modelling and Optimisation of Cyanobacterial C-phycocyanin Production Process by Artificial Neural Network

del Rio-Chanona, Ehecatl Antonio; Manirafasha, Emmanuel; Zhang, Dongda; Yue, Qian; Jing, Keju
Fonte: Elsevier Publicador: Elsevier
Tipo: Article; accepted version
EN
Relevância na Pesquisa
46.08%
This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.algal.2015.11.004; Artificial neural networks have been widely applied in bioprocess simulation and control due to their advantageous properties. However, their feasibility in long-term photo-fermentation process modelling and prediction as well as their efficiency on process optimisation have not been well studied so far. In the current study, an artificial neural network was constructed to simulate a 15-day fed-batch process for cyanobacterial C-phycocyanin production, which to the best of our knowledge has never been conducted. To guarantee the accuracy of artificial neural network, two strategies were implemented. The first strategy is to generate artificial data sets by adding random noise to the original data set, and the second is to choose the change of state variables as training data output. In addition, the first strategy showed the distinctive advantage of reducing the experimental effort in generating training data. By comparing with current experimental results, it is concluded that both strategies give the network great modelling and predictive power to estimate the entire fed-batch process performance...

Modeling of Noisy Spindle Dynamics Reveals Separable Contributions to Achieving Correct Orientation; Dynamic modelling reveals the separable contributions to achieving correct spindle orientation in a noisy system

Corrigan, Adam M.; Shrestha, Roshan; Draviam, Viji M.; Donald, Athene M.
Fonte: Elsevier Publicador: Elsevier
Tipo: Article; accepted version
EN
Relevância na Pesquisa
46.1%
This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.bpj.2015.08.014; The mechanisms by which the mammalian mitotic spindle is guided to a predefined orientation through microtubule-cortex interactions have recently received considerable interest, but there has been no dynamic model that describes spindle movements towards the preferred axis in human cells. Here, we develop a dynamic model based on stochastic activity of cues anisotropically positioned around the cortex of the mitotic cell and we show that the mitotic spindle does not reach equilibrium prior to chromosome segregation. Our model successfully captures the characteristic experimental behaviour of noisy spindle rotation dynamics in human epithelial cells, including a weak underlying bias in the direction of rotation, suppression of motion close to the alignment axis, and the effect of the aspect ratio of the interphase cell shape in defining the final alignment axis. We predict that the force exerted per cue has a value which minimizes the deviation of the spindle from the predefined axis. The model has allowed us to systematically explore the parameter space around experimentally relevant configurations, and predict the mechanistic function of a number of established regulators of spindle orientation...

Computational fluid dynamic modelling of two phase flow in a hydrocyclone

Leeuwner,M.J.; Eksteen,J.J.
Fonte: Journal of the Southern African Institute of Mining and Metallurgy Publicador: Journal of the Southern African Institute of Mining and Metallurgy
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2008 EN
Relevância na Pesquisa
46.13%
Computational fluid dynamic (CFD) modelling is used to research the complex flow structures that exist in a hydrocyclone. By simulation of a two phase (water and air) flow system, the internal flow and multiphase interactions are investigated. The suitability of CFD modelling as a design tool is further evaluated by examining the effect of varying device dimensions. Three hydrocyclone geometries, used in previous studies, are specified. A transient simulation approach, which employs the Reynolds Stress Model as turbulence model and the Volume of Fluid model as multiphase model, is followed. Results are validated qualitatively against experimental measurements from the previous studies.