Direct Monte Carlo simulation of turbulent drag reduction by rigid fibers in a channel flow

Moosaie, Amin; Manhart, Michael

doi:10.1007/s00707-013-0919-x

Cited by 25 publications

(20 citation statements)

References 68 publications

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“…Moosaie and Manhart [21] developed a two-way coupled direct solver based on a Lagrangian Monte-Carlo method and used it to study drag reduction in a turbulent channel flow caused by rigid microfiber additives. This was the first time to simulate fiber-induced turbulent drag reduction by means of a direct method.…”

Section: Accepted M M a N U mentioning

confidence: 99%

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On the structure of vorticity and near-wall partial enstrophy in fibrous drag-reduced turbulent channel flow

Moosaie

Manhart

2015

Journal of Non-Newtonian Fluid Mechanics

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Section: Accepted M M a N U mentioning

confidence: 99%

“…In this paper, the structure of the vorticity and near-wall partial enstrophy are scrutinized based on the DNS database of [21] for a fibrous drag-reduced flow. The modifications in the fibrous flow as compared to the Newtonian flow are shown and discussed.…”

Section: Accepted M M a N U mentioning

confidence: 99%

On the structure of vorticity and near-wall partial enstrophy in fibrous drag-reduced turbulent channel flow

Moosaie

Manhart

2015

Journal of Non-Newtonian Fluid Mechanics

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“…This approach is \exact" in a sense that it does not require any closure model. Moosaie and Manhart [8] proposed a direct Monte-Carlo method for the two-way coupled simulation dilute ber suspension ows and used this approach to study turbulent drag reduction in a channel ow. They used this method to study the structure of vorticity and near-wall partial enstrophy [9] and the pressure-strain correlation [10] in brous drag-reduced turbulent channel ow.…”

Section: Introductionmentioning

confidence: 99%

On the orientation dynamics and viscoelasticity of Brownian rigid disklike particles suspended in a shear flow

Moosaie

2017

Scientia Iranica

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Abstract. In this paper, numerical simulations are employed to study the orientation behavior of a dilute suspension of Brownian rigid disklike particles in a simple shear ow. Also, the viscoelasticity of such a suspension is analyzed by considering the stress budget of the two-phase material. A direct Monte-Carlo simulator as well as the moment approximation approaches with two di erent closure models are used to produce the data. Results are compared by available experimental and analytical data, and a very good agreement is established. After the validation of the simulators, the results are presented and discussed. Di erent P eclet numbers and shape factors of particles are considered and their e ects on various quantities are presented, e.g. particle orientations in space, viscous and elastic contributions to the non-Newtonian stress tensor, etc.

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“…Based on work by Daoudi and Brochard [15] he concluded that the elongational viscosity theory could not be correct due to the absence of the coil-stretch transition for polymers undergoing randomly fluctuating stresses in a turbulent velocity field, and reasoned that drag reduction had to be the result of the elastic properties of polymers instead [16,17]. Based on experimental work, theory, and simulations, there is support for both theories [18]. Since fibers do not have an elastic backbone their drag reducing effect is caused by viscosity effects, and if elastic theory is right, it has to be concluded that fibers and polymers have different drag reducing mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Rotational relaxation time as unifying time scale for polymer and fiber drag reduction

Boelens

Muthukumar

2016

Phys. Rev. E

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Using hybrid Direct Numerical Simulation with Langevin dynamics, a comparison is performed between polymer and fiber stress tensors in turbulent flow. The stress tensors are found to be similar, suggesting a common drag reducing mechanism in the onset regime for both flexible polymers and rigid fibers. Since fibers do not have an elastic backbone, this must be a viscous effect. Analysis of the viscosity tensor reveals that all terms are negligible, except the off-diagonal shear viscosity associated with rotation. Based on this analysis, we identify the rotational orientation time as the unifying time scale setting a new time criterion for drag reduction by both flexible polymers and rigid fibers.

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Direct Monte Carlo simulation of turbulent drag reduction by rigid fibers in a channel flow

Cited by 25 publications

References 68 publications

On the structure of vorticity and near-wall partial enstrophy in fibrous drag-reduced turbulent channel flow

On the structure of vorticity and near-wall partial enstrophy in fibrous drag-reduced turbulent channel flow

On the orientation dynamics and viscoelasticity of Brownian rigid disklike particles suspended in a shear flow

Rotational relaxation time as unifying time scale for polymer and fiber drag reduction

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