Suscripción a Biblioteca: Guest
Fifth International Symposium on Turbulence and Shear Flow Phenomena
August, 27-29, 2007, Technische Universität München, Munich, Germany

DOI: 10.1615/TSFP5

VORTEX STRUCTURES AND TURBULENT STATISTICS IN TURBULENT FLOW BEHIND AN ORIFICE

pages 823-828
DOI: 10.1615/TSFP5.1290
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SINOPSIS

Direct numerical simulation (DNS, hereafter) of a turbulent channel flow with an orifice has been performed in order to investigate the turbulent statistics and the vortex structures behind the orifice. The Reynolds numbers based on the friction velocity and the channel half width are 10 − 600. In the wake region, the mean flow becomes asymmetric in wall-normal direction by the Coanda effect. Large-scale vortices are generated at the height of the orifice edges. These vortices become deformed in various scenarios and break up into disordered small-scale structures in the shear layers behind the orifice. The small-scale vortices are converted toward the channel center. The contraction effect can be observed just behind the orifice. The turbulent kinetic energy and the Reynolds stresses increase in the free shear layers. In addition, we classify the wake region based upon the budgets of the Reynolds stresses. The several differences are found in the Reynolds stress budgets between in this study and for a backward-facing step turbulence.

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