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Effect of Reynolds number and concentration on modulation of turbulence by finite size neutrally buoyant particles

Wang, Guiquan and Abbas, Micheline and Climent, Eric Effect of Reynolds number and concentration on modulation of turbulence by finite size neutrally buoyant particles. (2016) In: 9th International Conference on Multiphase Flow (ICMF 2016), 22 May 2016 - 27 May 2016 (Florence, Italy). (Unpublished)

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Abstract

Direct numerical simulations of particle laden flow are carried out with the Force-Coupling Method to study the effect of finitesize neutrally buoyant particles on turbulent plane Couette flow. Two particle sizes and various concentrations (from 1 to 10%) are investigated for different Reynolds numbers above the transition to turbulence. Our results show that particle dispersion is determined by a balance between hydrodynamic wall repulsion, turbulent mixing and particle induced self-diffusion. Due to the presence of particles, close to the wall, turbulence intensity is attenuated in streamwise direction but is increased in wall-normal direction. This effect is enhanced by larger particles. The stress budget is also modified with two additional components, originating from particle rigidity (Stresslet) and particle Reynolds stress. The Stresslet contribution is stronger near the wall where the strain rate is the largest whereas maximum particle turbulent stress occurs in the core region where cross-gradient mixing is induced by turbulent flow structures. Reynolds stress budgets show no significant modulation of flow turbulence by particles. The viscous dissipation rate is the main component enhanced by particles near the transition threshold.

Item Type:Conference or Workshop Item (Speech)
Additional Information:The Re_p in the table1 is 4.38 5.83 and 8.75 for increasing Re_b
Audience (conference):International conference without published proceedings
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Université de Toulouse > Université Paul Sabatier-Toulouse III - UPS (FRANCE)
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Deposited By: Guiquan WANG
Deposited On:22 Jul 2016 11:57

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