PANGAEA_997505 Dataset of direct numerical simulations of turbulent mixing in a T-shaped mixer for Reynolds number up to 2000, Schmidt number unity and laminar inlets Zamani Asl, Mohammad Mehdi; Avila, Marc Dataset of direct numerical simulations of turbulent mixing in a T-shaped mixer for Reynolds number up to 2000, Schmidt number unity and laminar inlets 2026-10-30 PANGAEA Dataset https://doi.pangaea.de/10.1594/PANGAEA.997505 Investigator Mohammad Mehdi Zamani Asl mehdi.zamani@zarm.uni-bremen.de Earth Science Binary Object Binary Object (File Size) Figure Title File name File format Description geoscientificInformation turbulence simulation turbulence theory turbulent mixing Numerical simulated Complete unrestricted CC-BY-4.0: Creative Commons Attribution 4.0 International English PANGAEA Data Publisher for Earth & Environmental Science https://www.pangaea.de/ Data Center Contact Michael Diepenbroek info@pangaea.de

Leobener Str.

Bremen Bremen 28359 Germany online 168 data points text/tab-separated-values Zamani Asl, Mohammad Mehdi; Avila, Marc (2026): Stages of turbulence generation and decay in a T-shaped mixer. Journal of Fluid Mechanics, 1044, A17, https://doi.org/10.1017/jfm.2026.12098

Despite its widespread use as a model configuration for investigating mixing processes in chemical engineering, the turbulent regime of the T-shaped mixer remains relatively unexplored, in contrast to its well-documented transitional behaviour. To address this gap, we performed direct numerical simulations at Reynolds numbers up to Re = 2000 with a Schmidt number of Sc = 1 with spectral-element solver Nek5000. The results reveal a streamwise evolution characterised by two distinct regions before the flow approaches a fully developed duct-flow state. In the vicinity of the junction, the dynamics are dominated by a jet-like structure that displays approximate self-similarity resembling that of transitional planar jets. Downstream of this region, turbulence undergoes a decay process in which turbulent kinetic energy, dissipation, and scalar variance exhibit power-law scaling. Interestingly, the velocity-related decay exponents are characteristic of turbulence confined within bounded domains, whereas scalar variance decays at a rate consistent with unbounded turbulent flows. This difference can be explained by the spatial development of the mixing process: although turbulent fluctuations have spread across the entire channel cross-section by the end of the jet region, scalar homogenisation continues to advance laterally from the channel centre toward the walls within the decay region. In addition, the mean scalar distribution retains an error-function shape in the transverse direction, reminiscent of laminar mixing. The resulting streamwise development of the mean mixing state is described using an effective diffusion coefficient that varies along the channel. This dataset provides all the post-processed data necessary to reproduce the figures in the manuscript (doi:10.1017/jfm.2026.12098). Further, original Nek5000 binary output files (.f) can be used to extract simulation data at arbitrary spatial coordinates within the T-mixer for the averaged TKE quantities and scalar variance. Instantaneous velocity and scalar fields of the simulations are provided that allow to restart all simulations in Nek5000. ** For all details see the full metadata description at "https://doi.pangaea.de/10.1594/PANGAEA.997505"!

https://doi.org/10.1017/jfm.2026.12098 Stages of turbulence generation and decay in a T-shaped mixer DIF 9.4 2026-10-30 2026-10-30