Zamani Asl Mohammad Mehdi mehdi.zamani@zarm.uni-bremen.de 0000-0002-1322-6258 Center of Applied Space Technology and Microgravity ZARM https://www.zarm.uni-bremen.de/de/ Avila Marc marc.avila@zarm.uni-bremen.de 0000-0001-5988-1090 Center of Applied Space Technology and Microgravity ZARM https://www.zarm.uni-bremen.de/de/ 2026 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 dataset https://doi.pangaea.de/10.1594/PANGAEA.997505 2026-10-30T10:16:41 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. Zamani Asl Mohammad Mehdi mehdi.zamani@zarm.uni-bremen.de 0000-0002-1322-6258 Avila Marc marc.avila@zarm.uni-bremen.de 0000-0001-5988-1090 2026 Stages of turbulence generation and decay in a T-shaped mixer journal article Journal of Fluid Mechanics 1044 https://doi.org/10.1017/jfm.2026.12098 A17 168 CC-BY-4.0 Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ Binary Object Binary Numerical simulated Zamani Asl Mohammad Mehdi mehdi.zamani@zarm.uni-bremen.de 0000-0002-1322-6258 Binary Binary Object (File Size) Binary (Size) Bytes Numerical simulated Zamani Asl Mohammad Mehdi mehdi.zamani@zarm.uni-bremen.de 0000-0002-1322-6258 Binary (Size) [Bytes] Figure Fig Numerical simulated Zamani Asl Mohammad Mehdi mehdi.zamani@zarm.uni-bremen.de 0000-0002-1322-6258 Fig Title Title Numerical simulated Zamani Asl Mohammad Mehdi mehdi.zamani@zarm.uni-bremen.de 0000-0002-1322-6258 Title File name File name Numerical simulated Zamani Asl Mohammad Mehdi mehdi.zamani@zarm.uni-bremen.de 0000-0002-1322-6258 File name File format File format Numerical simulated Zamani Asl Mohammad Mehdi mehdi.zamani@zarm.uni-bremen.de 0000-0002-1322-6258 File format Description Description description Numerical simulated Zamani Asl Mohammad Mehdi mehdi.zamani@zarm.uni-bremen.de 0000-0002-1322-6258 Description CurationLevelC Enhanced curation https://wiki.pangaea.de/wiki/Curation_levels turbulence simulation turbulence theory turbulent mixing author110988 author70364 curlevel30 inst20763 journal8744 license21 method15014 param146419 param16143 param25541 param50001 param7055 param96152 pi110988 ref142169 term40710 term76163 term78624 term78625