Turbulent drag reduction using fluid spheres

Journal article (2013)

Authors

J.J.J. Gillissen ChemE/Transport Phenomena - AS
Research Group
ChemE/Transport Phenomena (AS) (TU Delft)
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Published Date

2013

Language

English

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Faculty

Applied Sciences

Department

ChemE/Chemical Engineering

Research Group

ChemE/Transport Phenomena

Abstract

Using direct numerical simulations of turbulent Couette flow, we predict drag reduction in suspensions of neutrally buoyant fluid spheres, of diameter larger than the Kolmogorov length scale. The velocity fluctuations are enhanced in the streamwise direction, and reduced in the cross-stream directions, which is similar to the more studied case of drag reduction using polymers. Despite these similarities, the drag reduction mechanism is found to originate in the logarithmic region, while the buffer region contributes to a slight drag increase, which is opposite to polymer-induced drag reduction. Another striking difference is the reduction of the turbulent energy at the large scales and an enhancement at the small scales.


(Received July 20 2011)

(Revised October 08 2012)

(Accepted October 11 2012)