tailieunhanh - Engineering Turbulence Modelling and Experiments 6_2

These proceedings contain the papers presented at the ERCOFTAC International Symposium on Engineering Turbulence Modelling and Measurements - ETMM6 - held at Villasimius, Sardinia, Italy, in the period May 23-25, 2005. The symposium followed the previous five conferences on the topic of engineering turbulence modelling and measurements held in Dubrovnik, Yugoslavia, in 1990, Florence, Italy, in 1993, Crete, Greece, in 1996, Corsica, France, in 1999 and Mallorca, Spain, in 2002, but was held for the first time under the aegis of ERCOFTAC (European Research Community on Flow, Turbulence and Combustion). The proceedings of the previous conferences were also published by Elsevier | 481 Engineering Turbulence Modelling and Experiments 6 w. Rodi Editor 2005 Elsevier Ltd. All rights reserved. THE ROLE OF PRESSURE-VELOCITY CORRELATION IN OSCILLATORY FLOW BETWEEN A PAIR OF BLUFF BODIES Shinnosuke Obi Norihiko Tokai and Keita Sakai Department of Mechanical Engineering Keio University Yokohama 223-8522 Japan ABSTRACT Turbulent flow measurements were conducted between two bluff bodies set in uniform flow in tandem arrangement. The velocity obtained with PIV were averaged with respect to either time or phase of periodic pressure oscillation induced by vortex shedding from the bluff body . Reynolds decomposition or three-level decomposition. The Reynolds stress caused by periodic fluid motion was found excessively large compared with those related to turbulent fluctuation in entire flow field. The PIV data were used to solve discrete Poisson equation of instantaneous pressure. The effect of organized vortex motion was recognized as the strong correlation between velocity and pressure gradient which could explain the poor performance of RANS turbulence models in predicting this kind of flows. KEYWORDS Turbulent Wake PIV Reynolds Stress Pressure-Velocity Correlation URANS Three-level Decomposition INTRODUCTION Turbulence models based on the Reynolds-averaged Navier-Stokes RANS approach often fail to predict flows associated with massive separation in contrast to LES that correctly captures large-scale turbulent fluid motion typically found in such flows. It is generally recognized that the poor performance of the RANS models is due to the shortcomings of the statistical approach itself in representing the coherent structure in turbulence. On the other hand the development of conventional RANS models have relied upon the knowledge of simple shear flows in nearly equilibrium state hence it is likely that the turbulent transport process which is remarkable in non-equilibrium flows is not correctly incorporated in the existing models. In particular the .

• Cơ khí - Chế tạo máy
• CFD codes
• industrial turbulent
• multiphase flows
• Turbulence Modelling
• algebraic Reynolds
• LES solution
• Turbulence modelling
• Boiling flow
• Channel mentioned above
• INSCSP R7 Standard Problem
• An introduction to computational fluid dynamics
• Computational fluid dynamics
• Boundary conditions
• Turbulence and ít modelling
• Difusion problems
• The finite volume method