DOI: 10.1615/ICHMT.2012.ProcSevIntSympTurbHeatTransfPal
ISBN Print: 978-1-56700-302-4
ISSN: 2377-2816
Study of the turbulent wake behind a cylinder for different Richardson numbers
RESUMO
The turbulent wake of a horizontal cylinder in cross-flow is experimentally investigated by means of flow visualizations and 2D Particle Image Velocimetry (PIV). Within this investigation the Reynolds number was chosen to be 1000 and the Richardson number was varied between 0 and 2.77. Results show that for small Richardson numbers the fluctuating activity in the wake of the cylinder is decreased in the shear-layers region and the wake structure is slightly disturbed whereas the latter undergoes a significant upward deflection for higher Richardson numbers as buoyancy effects are no more negligible. Moreover the analysis of instantaneous flow visualizations show the existence of mushroom-like structures and Kelvin-Helmholtz instabilities in the wake of the cylinder when buoyancy effects are predominant. These structures start to emerge in the wake of the cylinder for Ri=1 and develop themselves with the increase of the Richardson number.