A high-fidelity numerical database for free-stream-turbulence-induced transition under varying pressure gradients
Abstract
Free-stream-turbulence-induced transition under streamwise-varying pressure gradients, as encountered on turbine blades, has received much less attention in high-fidelity simulations than its zero-pressure-gradient counterpart. The ERCOFTAC T3 experiments provide a carefully documented reference for this problem and remain central to transition-model calibration. Complementing them with full-field, three-dimensional data opens new opportunities for the development of physics-based and machine-learning transition models. To this end, wall-resolved implicit large-eddy simulations of the T3A, T3B, and T3C2--C5 flat-plate cases are performed with a high-order compressible solver, using an upstream slip-wall block that lets the synthetic free-stream turbulence develop up to the leading edge. The simulations reproduce well the measured transition locations, integral quantities, and velocity profiles, and predict a separation bubble near the end of the plate for the lowest-Reynolds-number case T3C4. As the Reynolds number decreases and transition moves into the adverse-pressure-gradient region, the mechanism evolves continuously from classical bypass transition to transition governed by the tendency of the laminar boundary layer to separate, up to separation-induced transition. Intermittency, conditioned statistics, and Reynolds-stress budgets document this evolution and the associated non-equilibrium effects, which challenge current RANS transition models.
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BibTeX
@misc{zemmour2026highfidelity,
title = {{A high-fidelity numerical database for free-stream-turbulence-induced transition under varying pressure gradients}},
author = {Louenas Zemmour and Xavier Gloerfelt and Paola Cinnella},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2606.20139},
eprint = {2606.20139},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.20139},
}
RIS
TY - UNPB
TI - A high-fidelity numerical database for free-stream-turbulence-induced transition under varying pressure gradients
AU - Louenas Zemmour
AU - Xavier Gloerfelt
AU - Paola Cinnella
PY - 2026
DA - 2026/10/20
PB - arXiv
DO - 10.48550/arxiv.2606.20139
UR - https://arxiv.org/abs/2606.20139
AB - Free-stream-turbulence-induced transition under streamwise-varying pressure gradients, as encountered on turbine blades, has received much less attention in high-fidelity simulations than its zero-pressure-gradient counterpart. The ERCOFTAC T3 experiments provide a carefully documented reference for this problem and remain central to transition-model calibration. Complementing them with full-field, three-dimensional data opens new opportunities for the development of physics-based and machine-learning transition models. To this end, wall-resolved implicit large-eddy simulations of the T3A, T3B, and T3C2--C5 flat-plate cases are performed with a high-order compressible solver, using an upstream slip-wall block that lets the synthetic free-stream turbulence develop up to the leading edge. The simulations reproduce well the measured transition locations, integral quantities, and velocity profiles, and predict a separation bubble near the end of the plate for the lowest-Reynolds-number case T3C4. As the Reynolds number decreases and transition moves into the adverse-pressure-gradient region, the mechanism evolves continuously from classical bypass transition to transition governed by the tendency of the laminar boundary layer to separate, up to separation-induced transition. Intermittency, conditioned statistics, and Reynolds-stress budgets document this evolution and the associated non-equilibrium effects, which challenge current RANS transition models.
ER -