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Journal of Flow Visualization and Image Processing
SJR: 0.161 SNIP: 0.312 CiteScore™: 0.1

ISSN Imprimer: 1065-3090
ISSN En ligne: 1940-4336

Journal of Flow Visualization and Image Processing

DOI: 10.1615/JFlowVisImageProc.v10.i12.60
14 pages

ON THE BEHAVIOR OF POD MODES OF THE FLOW PAST A PERFORATED PLATE

Giancarlo Alfonsi
Fluid Dynamics Laboratory, Universita della Calabria, Via P. Bucci 42b, 87036 Rende (Cosenza), Italy
Leonardo Primavera
Fluid Dynamics Laboratory, Universita della Calabria, Via P. Bucci, Cubo 42b, 87036 Rende (Cosenza), Italy
Riccardo Felisari
Dipartimento di Ingegneria Idraulica, Politecnico di Milano Piazza L. da Vinci 32, 20133 Milano, Italy

RÉSUMÉ

The temporal behavior of coherent structures of turbulence in the case of a multiple interacting turbulent jet flow developing downstream from a perforated plate is investigated. The Proper Orthogonal Decomposition (POD) is applied to extract the coherent motions from a turbulent flow database of numerical nature obtained with the use of a finite-element computational code for the numerical integration of the Navier–Stokes equations at Re = 13300; for turbulence modeling the Large Eddy Simulation (LES) approach is followed and the Smagorinsky Sub Grid-Scale model (SGS) is used. The three-dimensional time-dependent velocity field past the perforated plate is computed and 400 time steps of the turbulent statistically steady state are considered for the decomposition of the flow field onto two appropriate computational subdomains. "Reduced" velocity fields, each reflecting the contribution of the first four most energetic POD modes containing up to 96.24% and 95.82% of the turbulent kinetic energy of the originary flow field, respectively, are reconstructed. Results are presented in terms of temporal evolution of the turbulent kinetic energy of the four most energetic eigenmodes of each subdomain, showing, in both cases, a rather regular temporal dynamics of the coherent structures (the POD modes) through different phases of the turbulent activity.