翻訳と辞書 Words near each other ・ Shear legs ・ Shear line ・ Shear line (locksmithing) ・ Shear Madness ・ Shear mapping ・ Shear matrix ・ Shear modulus ・ Shear pin ・ Shear rate ・ Shear strength ・ Shear strength (discontinuity) ・ Shear strength (soil) ・ Shear strength test ・ Shear stress ・ Shear thinning ・ Shear velocity ・ Shear wall ・ Shear Wave Elasticity Imaging ・ Shear wave splitting ・ Shear waves ・ Shear zone ・ Shear-tailed grey tyrant ・ Sheard ・ Sheard's Mill Covered Bridge ・ Shearer ・ Shearer Schoolhouse Revival ・ Shearer Stack ・ Shearer West ・ Shearer's Bar ・ Shearer's Covered Bridge 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 Shear velocity ： ウィキペディア英語版 Shear velocity Shear velocity, also called friction velocity, is a form by which a shear stress may be re-written in units of velocity. It is useful as a method in fluid mechanics to compare true velocities, such as the velocity of a flow in a stream, to a velocity that relates shear between layers of flow. Shear velocity is used to describe shear-related motion in moving fluids. It is used to describe: * Diffusion and dispersion of particles, tracers, and contaminants in fluid flows * The velocity profile near the boundary of a flow (see Law of the wall) * Transport of sediment in a channel Shear velocity also helps in thinking about the rate of shear and dispersion in a flow. Shear velocity scales well to rates of dispersion and bedload sediment transport. A general rule is that the shear velocity is about 1/10 of the mean flow velocity. $u\_=\backslash sqrt\}$ Where $\backslash tau$ is the shear stress in an arbitrary layer of fluid and $\backslash rho$ is the density of the fluid. Typically, for sediment transport applications, the shear velocity is evaluated at the lower boundary of an open channel: $u\_=\backslash sqrt\}$ Where $\backslash tau\_b$ is the shear stress given at the boundary. Shear velocity can also be defined in terms of the local velocity and shear stress fields (as opposed to whole-channel values, as given above). ==Friction Velocity in Turbulence== The friction velocity is often used as a scaling parameter for the fluctuating component of velocity in turbulent flows.〔H. Schlichting, K. Gersten, "Boundary-Layer Theory" 8th edition Springer 1999 ISBN 978-81-8128-121-0.〕 One method of obtaining the shear velocity is through non-dimensionalization of the turbulent equations of motion. For example, in a fully developed turbulent channel flow or turbulent boundary layer, the stream-wise momentum equation in the very near wall region reduces to: $0=-\backslash frac(\backslash overline)$. By integrating in the y-direction once, then non-dimensionalizing with an unknown velocity scale $u\_$ and viscous length scale $\backslash frac\; =\; \backslash nu\backslash frac\; -\; \backslash overline$ or $\backslash frac\; =\; \backslash frac\; +\; \backslash overline$. Since the right hand side is in non-dimensional variables, they must be of order 1. This results in the left hand side also being of order one, which in turn give us a velocity scale for the turbulent fluctuations (as seen above): $u\_\; =\; \backslash sqrt\}$. Here, $\backslash tau\_w$ refers to the local shear stress at the wall. 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「Shear velocity」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.