排序方式: 共有5条查询结果,搜索用时 0 毫秒
1
1.
2.
Upscaling Forchheimer law 总被引:2,自引:0,他引:2
Jean-Louis Auriault Christian Geindreau Laurent Orgéas 《Transport in Porous Media》2007,70(2):213-229
We investigate the high velocity flow in heterogeneous porous media. The model is obtained by upscaling the flow at the heterogeneity
scale where the Forchheimer law is assumed to be valid. We use the method of multiple scale expansions, which gives rigorously
the macroscopic behaviour without any prerequisite on the form of the macroscopic equations. We show that Forchheimer law
does not generally survive upscaling. The macroscopic flow law is strongly non-linear and anisotropic. A 2-point Padé approximation
of the flow law in the form of a Forchheimer law is given. However, this approximation is generally poor. These results are
illustrated in two particular cases: a layered composite porous media and a composite constituted by a square array of circular
porous inclusions embedded in a porous matrix. We show that non-linearities are sources of anisotropy. 相似文献
3.
The homogenisation method with multiple scale expansions is used to investigate the slow and isothermal flow of generalised Newtonian fluids through anisotropic porous media. From this upscaling it is shown that the first-order macroscopic pressure gradient can be defined as the gradient of a macroscopic viscous dissipation potential, with respect to the first-order volume averaged fluid velocity. The macroscopic dissipation potential is the volume-averaged of local dissipation potential. Using this property, guidelines are proposed to build macroscopic tensorial permeation laws within the framework defined by the theory of anisotropic tensor functions and by using macroscopic isodissipation surfaces. A quantitative numerical study is then performed on a 3D fibrous medium and with a Carreau–Yasuda fluid in order to illustrate the theoretical results deduced from the upscaling. 相似文献
4.
We investigate the filtration law of incompressible viscous Newtonian fluids in rigid non-inertial porous media, for example, rotating porous media. The filtration law is obtained by upscaling the flow at the pore scale. We use the method of multiple scale expansions which gives rigorously the macroscopic behaviour without any prerequisite on the form of the macroscopic equations. For finite Ekman numbers the filtration law is shown to resemble a Darcy's law, but with a non-symmetric permeability tensor which depends on the angular velocity of the porous matrix. We obtain the filtration analog of the Hall effect. For large Ekman numbers the filtration law is a small correction to the classical Darcy's law. The corrector is antisymmetric. In this case we recover a structure of law which is similar to phenomenological laws introduced in the literature, but with a dissimilar effective coefficient. 相似文献
5.
Viivi Koivu Maxime Decain Christian Geindreau Keijo Mattila Jean-Francis Bloch Markku Kataja 《International Journal of Computational Fluid Dynamics》2013,27(10):713-721
Feasibility of a method for finding flow permeability of porous materials, based on combining computerised X-ray micro-tomography and numerical simulations, is assessed. The permeability is found by solving fluid flow through the complex 3D pore structures obtained by tomography for actual material samples. We estimate overall accuracy of the method and compare numerical and experimental results. Factors contributing to uncertainty of the method include numerical error arising from the finite resolution of tomographic images and the rather small sample size available with the present tomographic techniques. The total uncertainty of computed values of permeability is, however, not essentially larger than that of experimental results. We conclude that the method provides a feasible alternative for finding fluid flow properties of the kind of materials studied. It can be used to estimate all components of permeability tensor and is useful in cases where direct measurements are not achievable. Analogous methods can be applied to other modes of transport, such as diffusion and heat conduction. 相似文献
1