Turbulence structure of polymer turbulent channel flow with and without macromolecular polymer structures

Kim, K.; Sirviente, A. I.

doi:10.1007/s00348-005-0954-z

Cited by 10 publications

(3 citation statements)

References 35 publications

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“…It has been suggested that such thickening of the viscous sublayer and change in velocity gradient are a product of decreasing mixing in this near-bed flow that is caused by a stabilization of the boundary layer streaks and a reduction in the rate of bursting of low-momentum fluid upwards into the flow (de Angelis et al 2002;Li et al 2006). This in turn reduces interactions between the inner and outer regions of the flow (Kim & Sirviente 2005). Measurements in clay-laden flows (Wang & Plate 1996;Baas & Best 2002, 2009) have shown a distinct 'sawtooth' pattern in the at-a-point time series from near the top of the viscous sublayer.…”

Section: Bedforms and Primary Current Stratification In Cohesive Sedimentioning

confidence: 99%

Predicting bedforms and primary current stratification in cohesive mixtures of mud and sand

Baas

Best

Peakall

2015

JGS

156

253

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The use of sedimentary structures as indicators of flow and sediment morphodynamics in ancient sediments lies at the very heart of sedimentology, and allows reconstruction of formative flow conditions generated in a wide range of grain sizes and sedimentary environments. However, the vast majority of past research has documented and detailed the range of bedforms generated in essentially cohesionless sediments that lack the presence of mud within the flow and within the sediment bed itself. Yet most sedimentary environments possess fine-grained sediments and recent work has shown how the presence of this fine sediment may substantially modify the fluid dynamics of such flows. It is increasingly evident that understanding the influence of mud, and the presence of cohesive forces, is essential to permit a fuller interpretation of many modern and ancient sedimentary successions. In this paper, the present state of knowledge on the stability of current- and wave-generated bedforms and their primary current stratification is reviewed, and a new extended bedform phase diagram is presented that summarizes the bedforms generated in mixtures of sand and mud under rapidly decelerated flows. This diagram provides a phase space using the variables of yield strength and grain mobility as the abscissa and ordinate axes, respectively, and defines the stability fields of a range of bedforms generated under flows that have modified fluid dynamics owing to the presence of suspended sediment within the flow. Our results also present unique data on a range of bedforms generated in such flows, whose recognition is essential to help interpret such deposits in the ancient sedimentary record, including the following: (1) heterolithic stratification, comprising alternating laminae or layers of sand and mud; (2) the preservation of low-amplitude bed-waves, large current ripples and bed scours with intrascour composite bedforms; (3) low-angle cross-lamination and long lenses and streaks of sand and mud formed by bed-waves; (4) complex stacking of reverse bedforms, mud layers and low-angle cross-lamination on the upstream face of bed scours; (5) planar bedding comprising stacked mud–sand couplets. Furthermore, the results shown herein demonstrate that flow variability is not required to produce deposits consisting of interbedded sand and muds, and that the nature of flaser, wavy and lenticular bedding ( sensu Reineck & Wunderlich 1968) may also need reconsideration in the deposits of such sediment-laden flows.

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Section: Bedforms and Primary Current Stratification In Cohesive Sedimentioning

confidence: 99%

Predicting bedforms and primary current stratification in cohesive mixtures of mud and sand

Baas

Best

Peakall

2015

JGS

156

253

View full text Add to dashboard Cite

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“…Laser Induced Fluorescence (LIF) flow visualization was also conducted to aid the assessment of the presence of such polymer structures. The results corresponding to wall injection of PAM for homogeneous and heterogeneous conditions have previously been reported in [13] and a more comprehensive analysis of the turbulence data can be found in Kim and Sirviente [12].…”

Section: Resultsmentioning

confidence: 94%

“…Measurements of the flow and the corresponding visualizations for wall injection of PAM solutions with and without polymer structures can be found in Kim et al [13], and a more detailed study of the turbulence structure can be found in Kim and Sirviente [12]. The structured data is used as basis for comparison with the results obtained from the centerline injection of PAM solutions.…”

Section: Wall Versus Centerline Injection Of a Polyacrylamide Polymermentioning

confidence: 99%

Wall Versus Centerline Polymer Injection in Turbulent Channel Flows

Kim

Sirviente

2006

Flow Turbulence Combust

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This experimental study compares the mean and turbulence characteristics of turbulent channel flows with polymer injection at the wall and at the centerline to assess the impact of the injection location on drag reduction. It also contrasts the drag reduction performance of a hydrolyzed polymer versus a non-ionic polymer under the same conditions. Wall injection of non-ionic and hydrolized polymers resulted in 23% and 9% larger drag reduction than corresponding centerline injection, respectively. In all cases, the polymer was structured and the presence of macromolecular polymer structures, even when concentrated mostly away from the wall, seemed to be able to affect the turbulence structure in the flow.

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Introduction

2012

Turbulent Drag Reduction by Surfactant Additives

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Turbulence structure of polymer turbulent channel flow with and without macromolecular polymer structures

Cited by 10 publications

References 35 publications

Predicting bedforms and primary current stratification in cohesive mixtures of mud and sand

Predicting bedforms and primary current stratification in cohesive mixtures of mud and sand

Wall Versus Centerline Polymer Injection in Turbulent Channel Flows

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