FN Archimer Export Format
PT J
TI The merging of Kelvin–Helmholtz vortices into large coherent flow structures in a high Reynolds number flow past a wall-mounted square cylinder
BT 
AF Mercier, Philippe
   Ikhennicheu, Maria
   Guillou, Sylvain
   Germain, Gregory
   Poizot, Emmanuel
   Grondeau, Mikaël
   Thiébot, Jérôme
   Druault, Philippe
AS 1:1;2:2;3:1;4:2;5:1;6:1;7:1;8:3;
FF 1:;2:PDG-REM-RDT-LCSM;3:;4:PDG-REM-RDT-LCSM;5:;6:;7:;8:;
C1 Normandie Université, UNICAEN LUSAC, EA 4253, 60 rue Max Pol Fouchet, CS 20082, 50130 Cherbourg-en-Cotentin, France
   Ifremer, Marine Structure Laboratory, 150 Quai Gambetta 62200 Boulogne sur Mer, France
   Sorbonne Université, CNRS, UMR 7190, Institut Jean Le Rond d’Alembert, F-75005 Paris, France
C2 UNIV CAEN NORMANDIE, FRANCE
   IFREMER, FRANCE
   UNIV SORBONNE, FRANCE
SI BOULOGNE
SE PDG-REM-RDT-LCSM
IN WOS Ifremer UPR
   copubli-france
   copubli-univ-france
IF 3.795
TC 14
UR https://archimer.ifremer.fr/doc/00617/72940/72147.pdf
LA English
DT Article
DE ;Turbulence;Coherent flow structure;Numerical simulation;Lattice Boltzmann Method;Large Eddy Simulation;Wall-mounted obstacles
AB Flows at tidal-stream energy sites are characterised by high turbulence intensities and by the occurrence of highly energetic large and coherent flow structures. The interaction of the flow with seabed roughness is suspected to play a major role in the generation of such coherent flow structures. The problem is introduced with canonical wall-mounted square obstacles representing abrupt changes of bathymetry, with high Reynolds number flow (Re = 250000). Two methods are used: a numerical model, based on the LBM (Lattice Boltzmann Method) combined with LES (Large Eddy Simulation) and an experimental set-up in a circulating tank. The numerical model is validated by comparison with experimental data. In the case of a wall-mounted square cylinder, large-scale turbulent structures are identified in experiments where boils at the free surface can be observed. LBM simulation allows their three-dimensional characterisation. The dynamic of such large-scale events is investigated by temporal, spatial and spectral numerical analysis. Results show that periodical Kelvin–Helmholtz vortices are emitted in the cylinder wake. Then, they merge to form larger and more coherent structures that rise up to the surface. A wavelet study shows that the emission frequency of the Kelvin–Helmholtz vortices is not constant over time. 
PY 2020
PD MAY
SO Ocean Engineering
SN 0029-8018
PU Elsevier BV
VL 204
UT 000530233700016
DI 10.1016/j.oceaneng.2020.107274
ID 72940
ER

EF