Stochastic transport in the presence of spatial disorder: Fluctuation-induced corrections to homogenization
Stochastic transport in the presence of spatial disorder: Fluctuation-induced corrections to homogenization
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DOI：
10.1103/physreve.94.042121
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发表时间：
2016-10-17
影响因子：
2.4
通讯作者：
Galla, Tobias
中科院分区：
文献类型：
--
作者：
Russell, Matthew J.;Jensen, Oliver E.;Galla, Tobias
出于自然运输系统中的不确定性量化，我们调查了一个基于个人的运输过程涉及粒子进行随机行走沿着线的点汇的强度是独立的随机变量。我们假设粒子通过一级动力学从系统中移除。我们分析了系统使用层次结构的方法时，汇稀疏分布，包括随机均匀化近似，产生明确的预测，由于汇强度波动的外在无序在稳态。外在噪声诱导的颗粒浓度的长程空间相关性，不像波动，由于单独的内在噪声。此外，平均浓度分布，平均超过内在和外在的噪音，是升高与相应的配置文件相比，从一个统一的汇分布，表明经典的均匀化近似可以是一个有偏的估计的真实均值。
Motivated by uncertainty quantification in natural transport systems, we investigate an individual-based transport process involving particles undergoing a random walk along a line of point sinks whose strengths are themselves independent random variables. We assume particles are removed from the system via first-order kinetics. We analyze the system using a hierarchy of approaches when the sinks are sparsely distributed, including a stochastic homogenization approximation that yields explicit predictions for the extrinsic disorder in the stationary state due to sink strength fluctuations. The extrinsic noise induces long-range spatial correlations in the particle concentration, unlike fluctuations due to the intrinsic noise alone. Additionally, the mean concentration profile, averaged over both intrinsic and extrinsic noise, is elevated compared with the corresponding profile from a uniform sink distribution, showing that the classical homogenization approximation can be a biased estimator of the true mean.