时间分辨体积速度测量与分析揭示的层流热柱形态、相互作用与演化：在地球地幔中的应用
Morphology, interactions, and evolution of laminar thermal plumes revealed by time-resolved volumetric velocity measurements and analysis: Application to Earth's mantle
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles（加州大学洛杉矶分校地球、行星与空间科学系）
- Department of Earth and Planetary Sciences, Harvard University（哈佛大学地球与行星科学系）
机构由 AI 辅助整理，请以论文原文为准。
中文总结 AI 辅助
通过4D速度测量研究高普朗特数瑞利-贝纳尔系统中成簇层流热柱的形态、相互作用与演化，揭示多种动力学行为并建立统一演化框架，为地幔对流模拟提供基准。
中文摘要 AI 辅助
含柱状对流在地球物理和工业流动的热输运中起着基础性作用。尽管孤立层流热柱的动力学已被广泛研究，但由于缺乏粘性对流（这在湍流界很常见）的四维（4D，空间和时间）流动测量，多柱系统中热柱的集体相互作用和演化仍缺乏定量表征。本文通过4D速度测量，对具有温度依赖性粘性的高普朗特数瑞利-贝纳尔系统中的成簇热柱动力学进行了时间分辨实验研究。基于我们配套的方法论（Bao和Lithgow-Bertelloni，2025），我们表征了数十个共存热柱的时空分布、形态演化及相互作用模式。我们识别出广泛的动力学行为谱——合并、分裂、分支、脉冲和头部脱离——这些行为源于热柱之间、多尺度流动以及演化的热边界层之间的耦合相互作用。我们将先前观察到的行为综合到一个统一的、时间分辨的热柱演化路径框架中。特征长度和时间尺度，包括间距和起始时间，与先前的理论和实验研究进行了比较。我们发现热柱更薄且最小间距更大。孤立热柱（如夏威夷型）的比例随流动演化而剧烈变化（0-60%）。我们的结果为地球类似条件下热柱的自组织和时空变异性提供了新见解，这对于理解地球化学演化和将热点熔岩的地球化学异常映射到深部源区至关重要。这些结果定量地补充了先前关于相互作用热柱的实验工作和数值研究，可作为与地幔对流地球动力学模拟进行比较的基准。
英文摘要
Plume-laden convection plays a fundamental role in thermal transport in geophysical and industrial flows. While the dynamics of isolated laminar plumes have been extensively studied, their collective interactions and evolution in a multi-plume system remains poorly quantified due to the lack of four-dimensional (4D, in space and time) flow measurements for viscous convection, common in the turbulence community. Here we present a time-resolved experimental study of clustered plume dynamics in a high-Prandtl-number Rayleigh-Bénard system with temperature-dependent viscosity from 4D velocity measurements. Building on our companion methodology (Bao and Lithgow-Bertelloni, 2025), we characterize the spatiotemporal distribution, morphological evolution, and interaction modes of tens of coexisting plumes. We identify a wide spectrum of dynamical behaviors--merging, splitting, branching, pulsing, and head detachment--that arise from coupled interactions among plumes, multiscale flow, and the evolving thermal boundary layers. We synthesize prior behaviors into a unified, time-resolved framework of plume evolutionary pathways. Characteristic length and timescales, including spacing and initiation times, are compared with previous theoretical and experimental studies. We find thinner plumes with greater minimum spacing. The fraction of isolated plumes (e.g., Hawaii-like) varies dramatically (0--60%) as the flow evolves. Our results provide new insight into plume self-organization and spatiotemporal variability under Earth-like conditions, crucial for understanding geochemical evolution and mapping geochemical anomalies from hotspot lavas to deep sources. These results quantitatively complement previous experimental work and numerical studies on interacting plumes, serving as a benchmark for comparison with geodynamical simulations of mantle convection.
