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Effects of polymer additives on turbophoresis in a turbulent channel flow

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Turbophoresis is the migration of inertial particles towards the wall in a wall-bounded flow induced by turbulence. In this work, we analyze the effects of drag reducing polymer additives on turbophoresis in a turbulent channel flow. The numerical data set is obtained from a direct numerical simulation (DNS) of a turbulent channel flow of a viscoelastic fluid and laden with particles of different inertia. The results indicate that polymer additives decrease the turbophoretic drift. We establish that turbophoresis is reduced because of the smaller wall-normal variation of wall-normal fluid velocity fluctuations that occurs in all drag reducing flows. Hence a reduction of turbophoresis should be a common feature of all drag reducing flows such as fiber, bubble suspensions and MHD.

Author(s):

Gaetano Sardina    
Linné FLOW Centre, KTH Mechanics
Sweden

Arash Nowbahar    
Department of Chemical Engineering, The City College of New York
United States

Francesco Picano    
Linné FLOW Centre, KTH Mechanics
Sweden

Luca Brandt    
Linné FLOW Centre, KTH Mechanics
Sweden