Synchronization in Navier-Stokes Turbulence and Its Role in Data-Driven Modeling

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• Masanobu Inubushi, DAMTP (visiting scholar); (Tokyo University of Science)
• Wednesday 12 February 2025, 14:00-15:00
• JDB Seminar RM.

If you have a question about this talk, please contact Anna Walczyk.

In Navier-Stokes (NS) turbulence, large-scale turbulent flows determine small-scale flows; in other words, small-scale flows are synchronized to large-scale flows. In 3D turbulence, previous numerical studies suggest that the critical length separating these two scales is determined by the Kolmogorov length. In this talk, I will introduce our theoretical framework for characterizing synchronization phenomena [1]. Specifically, it provides a computational method for the exponential rate of convergence to the synchronized state, and identifies the critical length based on the NS equations via the “transverse” Lyapunov exponent. I will also discuss the synchronization property of 2D NS turbulence and how it differs from the 3D case [2]. These insights into synchronization and critical length scales are essential for developing machine-learning closure models for turbulence, in particular their stable reproducibility [3]. Finally, I will illustrate how “generalized” synchronization is crucial for predicting chaotic dynamics [4].

[1] M. Inubushi, Y. Saiki, M. U. Kobayashi, and S. Goto, Characterizing small-scale dynamics of Navier-Stokes turbulence with transverse Lyapunov exponents: A data assimilation approach, Phys. Rev. Lett. 131, 254001 (2023). [2] M. Inubushi and C. P. Caulfield (in preparation). [3] S. Matsumoto, M. Inubushi, and S. Goto, Stable reproducibility of turbulence dynamics by machine learning, Phys. Rev. Fluids 9, 104601 (2024). [4] A. Ohkubo and M. Inubushi, Reservoir computing with generalized readout based on generalized synchronization, Sci. Rep. 14, 30918 (2024).

This talk is part of the Engineering Fluids Group Seminar series.

This talk is included in these lists:

• Acoustics Lab Seminars
• Engineering Department Acoustics/Combustion Student seminars
• Engineering Fluids Group Seminar
• JDB Seminar RM

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