Cascade-driven fragmentation-aggregation transitions in decaying turbulence
Abstract
In decaying turbulence, the turbulent cascade is not merely a passive background for breakup but an evolving stability boundary that dynamically selects the fragmentation-aggregation pathway. As turbulence decays, the Hinze scale sweeps through the bubble-size distribution, progressively eliminating the breakable population and driving a transition from a mixed breakup-coalescence regime to a self-sustaining pure-coalescence state. Our model predicts a critical turbulence decay exponent m=5/3, a transient mixed breakup-coalescence regime, and a late-stage pure-coalescence state with a universal coalescence hazard. Interestingly, the transient breakup acts as a catalyst that amplifies mixed-regime bubble growth relative to pure coalescence. Results from our direct numerical simulations of decaying homogeneous isotropic turbulence as well as high-Reynolds-number duct-flow experiments collapse onto the model predictions when expressed in terms of the measured decay rate. These results replace the conventional instantaneous Hinze criterion with a non-equilibrium, cascade-controlled framework for turbulent fragmentation and aggregation.
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BibTeX
@misc{kumar2026cascadedriven,
title = {{Cascade-driven fragmentation-aggregation transitions in decaying turbulence}},
author = {Vivek Kumar and Prasoon Suchandra and Shivam Prajapati and Suhas Jain and Cyrus Aidun},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.23273},
eprint = {2609.23273},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.23273},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Cascade-driven fragmentation-aggregation transitions in decaying turbulence
AU - Vivek Kumar
AU - Prasoon Suchandra
AU - Shivam Prajapati
AU - Suhas Jain
AU - Cyrus Aidun
PY - 2026
DA - 2026/09/20
PB - arXiv
DO - 10.48550/arxiv.2609.23273
UR - https://arxiv.org/abs/2609.23273
AB - In decaying turbulence, the turbulent cascade is not merely a passive background for breakup but an evolving stability boundary that dynamically selects the fragmentation-aggregation pathway. As turbulence decays, the Hinze scale sweeps through the bubble-size distribution, progressively eliminating the breakable population and driving a transition from a mixed breakup-coalescence regime to a self-sustaining pure-coalescence state. Our model predicts a critical turbulence decay exponent m=5/3, a transient mixed breakup-coalescence regime, and a late-stage pure-coalescence state with a universal coalescence hazard. Interestingly, the transient breakup acts as a catalyst that amplifies mixed-regime bubble growth relative to pure coalescence. Results from our direct numerical simulations of decaying homogeneous isotropic turbulence as well as high-Reynolds-number duct-flow experiments collapse onto the model predictions when expressed in terms of the measured decay rate. These results replace the conventional instantaneous Hinze criterion with a non-equilibrium, cascade-controlled framework for turbulent fragmentation and aggregation.
ER -