$$\newcommand{\bra}[1]{\left<#1\right|}\newcommand{\ket}[1]{\left|#1\right>}\newcommand{\bk}[2]{\left<#1\middle|#2\right>}\newcommand{\bke}[3]{\left<#1\middle|#2\middle|#3\right>}$$
X
INFORMAÇÕES SOBRE DIREITOS AUTORAIS


As obras disponibilizadas nesta Biblioteca Digital foram publicadas sob expressa autorização dos respectivos autores, em conformidade com a Lei 9610/98.

A consulta aos textos, permitida por seus respectivos autores, é livre, bem como a impressão de trechos ou de um exemplar completo exclusivamente para uso próprio. Não são permitidas a impressão e a reprodução de obras completas com qualquer outra finalidade que não o uso próprio de quem imprime.

A reprodução de pequenos trechos, na forma de citações em trabalhos de terceiros que não o próprio autor do texto consultado,é permitida, na medida justificada para a compreeensão da citação e mediante a informação, junto à citação, do nome do autor do texto original, bem como da fonte da pesquisa.

A violação de direitos autorais é passível de sanções civis e penais.
Coleção Digital

Avançada


Formato DC |



Título: EXPERIMENTS ON THE ADDITIONAL DYNAMIC PRESSURE IN THE FLOW RELATIVE BETWEEN SOLID PARTICLES AND VISCOUS FLUID
Autor: ROBERTO GUIMARAES PEREIRA
Instituição: PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO - PUC-RIO
Colaborador(es):  MAURICIO NOGUEIRA FROTA - ADVISOR
Nº do Conteudo: 33504
Catalogação:  05/04/2018 Idioma(s):  PORTUGUESE - BRAZIL
Tipo:  TEXT Subtipo:  THESIS
Natureza:  SCHOLARLY PUBLICATION
Nota:  Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio.
Referência [pt]:  https://www.maxwell.vrac.puc-rio.br/colecao.php?strSecao=resultado&nrSeq=33504@1
Referência [en]:  https://www.maxwell.vrac.puc-rio.br/colecao.php?strSecao=resultado&nrSeq=33504@2
Referência DOI:  https://doi.org/10.17771/PUCRio.acad.33504

Resumo:
Experiments concerning the relative motion of solid particles and viscous fluids, confined within cylinders of arbitrary cross-section (circular and quadrangular) have been conducted. For all cases experimentally investigated and for a flow regime extending from a very low particle Reynolds Number (Re less than 0.1) up to far beyond the Oseen s Regime, it has been shown that the additional pressure force to viscous drag ratio (Delta plus A/D) can be directly evaluated by means of parameters of the unperturbed flow. Accordingly to a recent theory (Brenner, 1962) the above statement which uses a Oseen s type linearization of the equation of motion, should only be expected for the very low particle Reynolds Number regime (Re < 2). Brenner (1962), using momentum and energy theorems applied to the relative motion of a particle and a confined viscous fluid has shown that, as a result of the relative motion, a finete shearing force acting on the cylinder walls must existis, even if the walls are infinitely distant from the particle perturbation. The generality of Brenner s theory concerning the cylinder geometry was also verified in the Stokes and in the Oseen s regimes. Experiments conducted in a short (1 m) circular cylinder, filled with a Newtonian fluid, provided the base line data set used to qualify the experimental technique used, within very low experimental uncertainties. Experiments conducted in a long square cylinder (3 m), allowed verification of the theory far beyond the theorectical regime. Measurements of the additional pressure drop created by the relative motion between a solid particle and the viscous fluid, confined in the square cylinder, cleary defined three regions: i) up to about Re ~ 50 it was found that the pressure force to Viscous drag ratio Delta P+A/D approximately 2.093 which should be expected only for Re < 2. By elementary momentum considerations, applied to the fluid control volume around the particle present in the flow, it can easily be show that this value of Delta P+A/D diferente than 1 confirms the existence of a finete shearing force on the far walls of the cylinder; ii) beyond Re = 50 and up to Re ~ 2500 a very complex and not completely understood transition occurs. At about Re ~ 50 an abrupt transition takes place forcing the value of Delta P+A/D to decrease. The ratio Delta P+A/D decreases asymptotically towards the value 1.0 wich corresponds to the situation of an unbounded fluid as can be predicted by the Momentum Principle; iii) for particle Reynolds Number Re > 2500, the Delta P+A/D approaches very closely the value 1.0. The largest flow regime investigated was Re ~ 36000 but, physically, there seems to be no reason to expect any change in the described behaviour. This work also discusses an accurate method for directly measuring the viscous drag force and the diminute dynamic pressure (~ 1 to 10 (-3) mm Hg) created by the motion of the particle.

Descrição Arquivo
COMPLETE  PDF  
Logo maxwell Agora você pode usar seu login do SAU no Maxwell!!
Fechar Janela



* Esqueceu a senha:
Senha SAU, clique aqui
Senha Maxwell, clique aqui