翻訳と辞書 Words near each other ・ Lambda Theta Phi ・ Lambda transition ・ Lambda Tucanae ・ Lambda Upsilon Lambda ・ Lambda Ursae Majoris ・ Lambda Ursae Minoris ・ Lambda Velorum ・ Lambda Virginis ・ Lambda Warszawa ・ Lambda-carrageenase ・ Lambda-CDM model ・ Lambda-connectedness ・ Lambda-mu calculus ・ Lambda1 Phoenicis ・ Lambda2 Fornacis ・ Lambda2 method ・ Lambdacism ・ Lambdaistanbul ・ Lambdalikevirus ・ LambdaMOO ・ LambdaNative ・ Lambdapapillomavirus ・ Lambdas ・ Lambdatorquevirus ・ Lambdavacuum solution ・ Lambdin ・ Lambdin P. Milligan ・ Lambdina ・ Lambdina fervidaria ・ Lambdina fiscellaria 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 Lambda2 method ： ウィキペディア英語版 Lambda2 method The Lambda2 method, or Lambda2 vortex criterion, is a detection algorithm that can adequately identify vortices from a three-dimensional velocity field.〔J. Jeong and F. Hussain. On the Identification of a Vortex. ''J. Fluid Mechanics'', 285:69-94, 1995.〕 The Lambda2 method is Galilean invariant, which means it produces the same results when a uniform velocity field is added to the existing velocity field or when the field is translated. ==Definition== The Lambda2 method consists of several steps. First we define the gradient velocity tensor $\backslash mathbf$; $$ \mathbf \equiv \nabla \vec = \begin \partial_x u_x & \partial_y u_x & \partial_z u_x \\ \partial_x u_y & \partial_y u_y & \partial_z u_y \\ \partial_x u_z & \partial_y u_z & \partial_z u_z \end, where $\backslash vec$ is the velocity field. The gradient velocity tensor is then decomposed into its symmetric and antisymmetric parts: $\backslash mathbf\; =\; \backslash frac^\backslash text\}$ and $\backslash mathbf\; =\; \backslash frac^\backslash text\},$ where T is the transpose operation. Next the three eigenvalues of $\backslash mathbf^2\; +\; \backslash mathbf^2$ are calculated so that for each point in the velocity field $\backslash vec$ there are three corresponding eigenvalues; $\backslash lambda\_1$, $\backslash lambda\_2$ and $\backslash lambda\_3$. The eigenvalues are ordered in such a way that $\backslash lambda\_1\; \backslash geq\; \backslash lambda\_2\; \backslash geq\; \backslash lambda\_3$. A point in the velocity field is part of a vortex core only if at least two of its eigenvalues are negative i.e. if . This is what gave the Lambda2 method its name. Using the Lambda2 method, a vortex can be defined as a connected region where $\backslash lambda\_2$ is negative. However, in situations where several vortices exist, it can be difficult for this method to distinguish between individual vortices 〔Jiang, Ming, Raghu Machiraju, and David Thompson. "Detection and Visualization of Vortices" ''The Visualization Handbook'' (2005): 295.〕 . The Lambda2 method has been used in practice to, for example, identify vortex rings present in the blood flow inside the human heart 〔ElBaz, Mohammed SM, et al. "Automatic Extraction of the 3D Left Ventricular Diastolic Transmitral Vortex Ring from 3D Whole-Heart Phase Contrast MRI Using Laplace-Beltrami Signatures." ''Statistical Atlases and Computational Models of the Heart. Imaging and Modelling Challenges.'' Springer Berlin Heidelberg, 2014. 204-211.〕 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「Lambda2 method」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.