Time-Dependent Visualization of Lagrangian Coherent Structures by Grid Advection
Time-Dependent Visualization of Lagrangian Coherent Structures by Grid Advection
复制标题
通过网格平流对拉格朗日相干结构进行时变可视化
DOI：
10.1007/978-3-642-15014-2_13
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
R. Peikert
中科院分区：
文献类型：
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作者：
F. Sadlo;Alessandro Rigazzi;R. Peikert
拉格朗日相干结构在非定常矢量场分析中起着重要的作用，因为它们代表了矢量场拓扑的时间依赖性模拟。如今，它们通常是作为向量场的有限时间李雅普诺夫指数中的脊而获得的。然而，该量的一个缺点是其非常高的计算成本，因为需要为空间-时间域中的每个样本计算轨迹。本文的一个重点是拉格朗日相干结构，与预定义的区域，如边界，即相关的流动附着和流动分离现象。它提出了一种有效的方法，计算有限时间的李雅普诺夫指数和它的高度脊只在这些地区，特别是网格平流的有限时间李雅普诺夫指数的时间序列的有效计算，利用时间相干性。
Lagrangian coherent structures play an important role in the analysis of unsteady vector fields because they represent the time-dependent analog to vector field topology. Nowadays, they are often obtained as ridges in the finite-time Lyapunov exponent of the vector field. However, one drawback of this quantity is its very high computational cost because a trajectory needs to be computed for every sample in the space-time domain. A focus of this paper are Lagrangian coherent structures that are related to predefined regions such as boundaries, i.e. related to flow attachment and flow separation phenomena. It presents an efficient method for computing the finite-time Lyapunov exponent and its height ridges only in these regions, and in particular,grid advection for the efficient computation of time series of the finite-time Lyapunov exponent, exploiting temporal coherence.