翻訳と辞書 Words near each other ・ Newtongrange ・ Newtongrange railway station ・ Newtongrange Star F.C. ・ Newtonhead railway station ・ Newtonhill ・ Newtonia ・ Newtonia (bird) ・ Newtonia (plant) ・ Newtonia camerunensis ・ Newtonia erlangeri ・ Newtonia hildebrandtii ・ Newtonia paucijuga ・ Newtonia, Missouri ・ Newtonian ・ Newtonian dynamics ・ Newtonian fluid ・ Newtonian gauge ・ Newtonian limit ・ Newtonian material ・ Newtonian motivations for general relativity ・ Newtonian potential ・ Newtonian telescope ・ Newtonianism ・ Newtoniellidae ・ Newtonin Moondram Vidhi ・ Newtonmore ・ Newtonmore Camanachd Club ・ Newtonmore railway station ・ Newtons (cookie) ・ Newtons Sleep Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Newtonian fluid ： ウィキペディア英語版 Newtonian fluid In continuum mechanics, a Newtonian fluid is a fluid in which the viscous stresses arising from its flow, at every point, are linearly proportional to the local strain rate—the rate of change of its deformation over time. That is equivalent to saying that those forces are proportional to the rates of change of the fluid's velocity vector as one moves away from the point in question in various directions. More precisely, a fluid is Newtonian only if the tensors that describe the viscous stress and the strain rate are related by a constant viscosity tensor that does not depend on the stress state and velocity of the flow. If the fluid is also isotropic (that is, its mechanical properties are the same along any direction), the viscosity tensor reduces to two real coefficients, describing the fluid's resistance to continuous shear deformation and continuous compression or expansion, respectively. Newtonian fluids are the simplest mathematical models of fluids that account for viscosity. While no real fluid fits the definition perfectly, many common liquids and gases, such as water and air, can be assumed to be Newtonian for practical calculations under ordinary conditions. However, non-Newtonian fluids are relatively common, and include oobleck (which becomes stiffer when vigorously sheared), or non-drip paint (which becomes thinner when sheared). Other examples include many polymer solutions (which exhibit the Weissenberg effect), molten polymers, many solid suspensions, blood, and most highly viscous fluids. Newtonian fluids are named after Isaac Newton, who first derived the relation between the rate of shear strain rate and shear stress for such fluids in differential form. ==Definition== An element of a flowing liquid or gas will suffer forces from the surrounding fluid, including viscous stress forces that cause it to gradually deform over time. These forces can be mathematically approximated to first order by a viscous stress tensor, which is usually denoted by $\backslash tau$. The deformation of that fluid element, relative to some previous state, can be approximated to first order by a strain tensor that changes with time. The time derivative of that tensor is the strain rate tensor, that expresses how the element's deformation is changing with time; and is also the gradient of the velocity vector field $v$ at that point, often denoted $\backslash nabla\; v$. The tensors $\backslash tau$ and $\backslash nabla\; v$ can be expressed by 3×3 matrices, relative to any chosen coordinate system. The fluid is said to be Newtonian if these matrices are related by the equation $\backslash mathbf\; =\; \backslash mathbf\; (\backslash nabla\; v)$ where $\backslash mu$ is a fixed 3×3×3×3 fourth order tensor, that does not depend on the velocity or stress state of the fluid. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Newtonian fluid」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.