TY  - CHAP
A1  - Valero, Daniel
A1  - Bung, Daniel B.
A1  - Erpicum, Sebastien
A1  - Dewals, Benjamin
T1  - Numerical study of turbulent oscillations around a cylinder: RANS capabilities and sensitivity analysis
T2  - Proceedings of the 37th IAHR World Congress August 13 – 18, 2017, Kuala Lumpur, Malaysia
Y1  - 2017
SN  - 2521-716X
SP  - 3126
EP  - 3135
ER  - 
TY  - JOUR
A1  - Valero, Daniel
A1  - Bung, Daniel B.
A1  - Erpicum, Sebastien
A1  - Peltier, Yann
A1  - Dewals, Benjamin
T1  - Unsteady shallow meandering flows in rectangular reservoirs: a modal analysis of URANS modelling
JF  - Journal of Hydro-environment Research
N2  - Shallow flows are common in natural and human-made environments. Even for simple rectangular shallow reservoirs, recent laboratory experiments show that the developing flow fields are particularly complex, involving large-scale turbulent structures. For specific combinations of reservoir size and hydraulic conditions, a meandering jet can be observed. While some aspects of this pseudo-2D flow pattern can be reproduced using a 2D numerical model, new 3D simulations, based on the unsteady Reynolds-Averaged Navier-Stokes equations, show consistent advantages as presented herein. A Proper Orthogonal Decomposition was used to characterize the four most energetic modes of the meandering jet at the free surface level, allowing comparison against experimental data and 2D (depth-averaged) numerical results. Three different isotropic eddy viscosity models (RNG k-ε, k-ε, k-ω) were tested. The 3D models accurately predicted the frequency of the modes, whereas the amplitudes of the modes and associated energy were damped for the friction-dominant cases and augmented for non-frictional ones. The performance of the three turbulence models remained essentially similar, with slightly better predictions by RNG k-ε model in the case with the highest Reynolds number. Finally, the Q-criterion was used to identify vortices and study their dynamics, assisting on the identification of the differences between: i) the three-dimensional phenomenon (here reproduced), ii) its two-dimensional footprint in the free surface (experimental observations) and iii) the depth-averaged case (represented by 2D models).
KW  - coherent structures
KW  - hydraulic modelling
KW  - model performance
KW  - Proper Orthogonal Decomposition
KW  - Q-criterion
Y1  - 2022
U6  - http://dx.doi.org/10.1016/j.jher.2022.03.002
SN  - 1570-6443
IS  - In Press
PB  - Elsevier
CY  - Amsterdam
ER  -