Valdecir alves dos santos - Academia.edu (original) (raw)
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O presente trabalho apresenta um estudo analitico/numerico do escoamento laminar de fluidos atrav... more O presente trabalho apresenta um estudo analitico/numerico do escoamento laminar de fluidos atraves de dutos retos de secao transversal arbitraria, obtendo resultados para parâmetros fluidodinâmicos de interesses, tais como: fator de atrito de Fanning, intervalos de numeros de Reynolds, assim como valores para tensao de cisalhamento e gradiente de pressao. Em cada duto e escolhido a melhor parametrizacao para as curvas que representam a geometria da secao transversal e a partir delas encontra-se um conjunto de funcoes bases que sao utilizadas para apresentar as solucoes analiticas das equacoes de momento linear e energia utilizando o metodo integral baseado em Galerkin. Para a simulacao numerica e utilizado o software Maple 17 que possibilita apresentar solucoes para o perfil de velocidade e temperatura, velocidade media,temperatura media e aproximacoes numericas para o numero de Poiseuille e Nusselt medio e local para cada numero de funcoes bases escolhidas. Os resultados sao reali...
Research, Society and Development, 2021
Fluid flow in concentric or eccentric annular ducts have been studied for decades due to large ap... more Fluid flow in concentric or eccentric annular ducts have been studied for decades due to large application in medical sciences and engineering areas. This paper aims to study fully developed fluid flow in straight ducts of concentric annular geometries (circular with circular core, elliptical with circular core, elliptical with elliptical core, and circular with elliptical core) using the Galerkin-based Integral method (GBI method). The choice of method was due to the fact that in the literature it is not applied in ducts of cross-sections of the annular shape with variations between circular and elliptical. Results of different hydrodynamics parameters such as velocity distribution, Hagenbach factor, Poiseuille number, and hydrodynamic entrance length, are presented and analyzed. In different cases, the predicted hydrodynamic parameters are compared with results reported in the literature and a good concordance was obtained.
Free space Green's functions are derived for graded materials in which the thermal conductivity v... more Free space Green's functions are derived for graded materials in which the thermal conductivity varies exponentially in one coordinate. Closed-form expressions are obtained for the steady-state diffusion equation, in two and three dimensions. The corresponding boundary integral equation formulations for these problems are derived, and the threedimensional case is solved numerically using a Galerkin approximation. The results of test calculations are in excellent agreement with exact solutions and finite element simulations.
O presente trabalho apresenta um estudo analitico/numerico do escoamento laminar de fluidos atrav... more O presente trabalho apresenta um estudo analitico/numerico do escoamento laminar de fluidos atraves de dutos retos de secao transversal arbitraria, obtendo resultados para parâmetros fluidodinâmicos de interesses, tais como: fator de atrito de Fanning, intervalos de numeros de Reynolds, assim como valores para tensao de cisalhamento e gradiente de pressao. Em cada duto e escolhido a melhor parametrizacao para as curvas que representam a geometria da secao transversal e a partir delas encontra-se um conjunto de funcoes bases que sao utilizadas para apresentar as solucoes analiticas das equacoes de momento linear e energia utilizando o metodo integral baseado em Galerkin. Para a simulacao numerica e utilizado o software Maple 17 que possibilita apresentar solucoes para o perfil de velocidade e temperatura, velocidade media,temperatura media e aproximacoes numericas para o numero de Poiseuille e Nusselt medio e local para cada numero de funcoes bases escolhidas. Os resultados sao reali...
Research, Society and Development, 2021
Fluid flow in concentric or eccentric annular ducts have been studied for decades due to large ap... more Fluid flow in concentric or eccentric annular ducts have been studied for decades due to large application in medical sciences and engineering areas. This paper aims to study fully developed fluid flow in straight ducts of concentric annular geometries (circular with circular core, elliptical with circular core, elliptical with elliptical core, and circular with elliptical core) using the Galerkin-based Integral method (GBI method). The choice of method was due to the fact that in the literature it is not applied in ducts of cross-sections of the annular shape with variations between circular and elliptical. Results of different hydrodynamics parameters such as velocity distribution, Hagenbach factor, Poiseuille number, and hydrodynamic entrance length, are presented and analyzed. In different cases, the predicted hydrodynamic parameters are compared with results reported in the literature and a good concordance was obtained.
Free space Green's functions are derived for graded materials in which the thermal conductivity v... more Free space Green's functions are derived for graded materials in which the thermal conductivity varies exponentially in one coordinate. Closed-form expressions are obtained for the steady-state diffusion equation, in two and three dimensions. The corresponding boundary integral equation formulations for these problems are derived, and the threedimensional case is solved numerically using a Galerkin approximation. The results of test calculations are in excellent agreement with exact solutions and finite element simulations.