Optimal trajectories for Bayesian olfactory search in turbulent flows: The low information limit and beyond.

IF 2.5 3区 物理与天体物理 Q2 PHYSICS, FLUIDS & PLASMAS
Physical Review Fluids Pub Date : 2025-04-01 Epub Date: 2025-04-09 DOI:10.1103/physrevfluids.10.044601
R A Heinonen, L Biferale, A Celani, M Vergassola
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引用次数: 0

Abstract

In turbulent flows, tracking the source of a passive scalar cue requires exploiting the limited information that can be gleaned from rare, randomized encounters with the cue. When crafting a search policy, the most challenging and important decision is what to do in the absence of an encounter. In this work, we perform high-fidelity direct numerical simulations of a turbulent flow with a stationary source of tracer particles, and obtain quasi-optimal policies (in the sense of minimal average search time) with respect to the empirical encounter statistics [1-3]. We study the trajectories under such policies and compare the results to those of the infotaxis heuristic. In the presence of a strong mean wind, the optimal motion in the absence of an encounter is zigzagging (akin to the well-known insect behavior "casting") followed by a return to the starting location. The zigzag motion generates characteristic t 1 / 2 scaling of the rms displacement envelope. By passing to the limit where the probability of detection vanishes, we connect these results to the classical linear search problem and derive an estimate of the tail of the arrival time pdf as a stretched exponential p ( T ) exp ( - k T ) for some k > 0 , in agreement with Monte Carlo results. We also discuss what happens as the wind speed becomes smaller.

湍流中贝叶斯嗅觉搜索的最优轨迹:低信息限制及超越。
在湍流中,追踪被动标量线索的来源需要利用有限的信息,这些信息可以从与线索的罕见随机接触中收集到。在制定搜索策略时,最具挑战性和最重要的决定是在没有遇到的情况下该怎么做。在这项工作中,我们对具有静止示踪粒子源的湍流进行了高保真的直接数值模拟,并获得了相对于经验遭遇统计的准最优策略(在最小平均搜索时间的意义上)[1-3]。我们研究了这些策略下的轨迹,并将结果与信息趋向性启发式的结果进行了比较。在强风存在的情况下,在没有遭遇的情况下,最佳的运动是之字形(类似于众所周知的昆虫行为“投射”),然后返回起始位置。锯齿形运动产生的特征为rms位移包络的1 / 2缩放。通过传递到检测概率消失的极限,我们将这些结果与经典线性搜索问题联系起来,并推导出到达时间pdf尾部的估计,作为k > 0的拉伸指数p (T) ~ exp (- k T),与蒙特卡罗结果一致。我们还讨论了当风速变小时会发生什么。
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来源期刊
Physical Review Fluids
Physical Review Fluids Chemical Engineering-Fluid Flow and Transfer Processes
CiteScore
5.10
自引率
11.10%
发文量
488
期刊介绍: Physical Review Fluids is APS’s newest online-only journal dedicated to publishing innovative research that will significantly advance the fundamental understanding of fluid dynamics. Physical Review Fluids expands the scope of the APS journals to include additional areas of fluid dynamics research, complements the existing Physical Review collection, and maintains the same quality and reputation that authors and subscribers expect from APS. The journal is published with the endorsement of the APS Division of Fluid Dynamics.
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