Supporting data for Matsuzawa, Zhu, et al., "Nonlinear Diffusion and Decay of a Blob of Turbulence Spreading Into a Quiescent Fluid", PNAS, (2026)

Paper: Nonlinear Diffusion and Decay of a Blob of Turbulence Spreading Into a Quiescent Fluid

Authors: Takumi Matsuzawa, Minhui Zhu, Nigel Goldenfeld, William T. M. Irvine

Description:This repository contains the data presented in Figures 1–5 of the paper, which examine the decay and propagation of turbulence generated by repeatedly colliding vortex rings. In the study, we also explored turbulence decay generated by oscillating a double grid.

Each folder contains the data used to produce the main figures. For Figures 1C–F and 4C–F, we present time slices of ensemble-averaged fields, including energy and enstrophy.

The original velocity field data is approximately 10 GB per sample. We performed 21, 10, and 10 replications for the blob, double oscillating grid, and single oscillating grid configurations, respectively. From these, Reynolds averaging was applied to extract the turbulent (fluctuating) components. 

Contents:Each folder contains HDF5 files with relevant data that made it into the plot.

E.g. Figure 2B_tegral_lengthscale.h5 contains/blob/t_t0: t-t0/blob/ell: ell (Integral length scale) from the blob experiments/blob/ell_scaled: ell / Lbox (Scaled integral length scale)...