Effect of macromolecular polymer structures on drag reduction in a turbulent channel flow

Kim, K.; Islam, Mohammad Tariqul; Shen, Xiaochun; Sirviente, A. I.; Solomon, Michael J.

doi:10.1063/1.1790731

Cited by 17 publications

(37 citation statements)

References 40 publications

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“…The facility used for this study is described in detail in [13]. The flow in the recirculating water channel is driven by a 0.076 m 3 /s centrifugal pump into a 5.99 cm wide by 59.94 cm high and 6.35 m long channel test section.…”

Section: Facilities Instrumentation and Experimental Proceduresmentioning

confidence: 99%

“…The experimental work on fully developed turbulent channel flows with polymer injection of Shen et al [20] and Kim et al [13] showed that for the same overall polymer concentration at the test section, larger drag reduction is obtained when polymer structures are present in the flow compared to a corresponding homogeneous polymer distribution. Kim et al [13] showed that the large bulk of the polymer structures concentrated in the neighborhood of the channel's centerline, inspite of injecting the polymer in the near wall region.…”

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confidence: 98%

“…Furthermore, the ionic character of the polymer is expected to play an important role. The aggregates formed by ionic polymers, held together by ionic and hydrogen bonds, are expected to be more resistant to degradation than polymer entanglements, more characteristic of non-ionic polymers [refer to 13]. The work of Vlachogiannis and Hanratty [28] have studied the effect of wall injection of aggregates into turbulent channel flows and found that small injection concentrations translate into large percentages of drag reduction.…”

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confidence: 98%

“…Kim et al [13] showed that the large bulk of the polymer structures concentrated in the neighborhood of the channel's centerline, inspite of injecting the polymer in the near wall region.…”

mentioning

confidence: 99%

“…This work aims to address these issues by using as benchmark reference the data gathered by Kim et al [13] in a channel flow at Reynolds number of 5.6 × 10 4 with polymer injection at the near wall, with injection concentrations, C i , of 1,000 ppm < C i < 10,000 ppm. The polymer used was a polyacrylamide, and it was shown that for C i > 3,000 ppm polymer entanglements were indeed present in the flow when the polymer solutions were injected at the channel wall.…”

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confidence: 99%

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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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Section: Facilities Instrumentation and Experimental Proceduresmentioning

confidence: 99%

mentioning

confidence: 98%

mentioning

confidence: 98%

“…Kim et al [13] showed that the large bulk of the polymer structures concentrated in the neighborhood of the channel's centerline, inspite of injecting the polymer in the near wall region.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

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Wall Versus Centerline Polymer Injection in Turbulent Channel Flows

Kim

Sirviente

2006

Flow Turbulence Combust

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Turbulence Production in the Low Polymer Drag Reduction Regime

Elsnab

White

Klewicki

2019

Springer Proceedings in Physics

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Streamwise velocity profiles and their wall-normal derivatives were used to investigate the properties of turbulent channel flow in the low polymer drag reduction (DR) regime (DR = 6.5% to 26%), as realized via polymer injection at the channel surface. Streamwise velocity data were obtained over a friction Reynolds number ranging from 650 to 1800 using the single velocity component version of molecular tagging velocimetry (1c-MTV). This adaptation of the MTV technique has the ability to accurately capture instantaneous profiles at very high spatial resolution (850 data points per wall-normal profile), and thus generate well-resolved derivative information as well. Owing to this ability, the present study is able to build upon and extend the recent numerical simulation analysis of White et al. (J. Fluid Mech. vol. 834, 2018) that examined the mean dynamical structure of polymer drag reduced channel flow at friction Reynolds numbers up to 1000. Consistently, the present mean velocity profiles indicate that the extent of the logarithmic region diminishes with increasing polymer concentration, while statistically significant increases in the logarithmic profile slope begin to occur for drag reductions less than 15%. Profiles of the streamwise velocity rms indicate that the maximum moves farther from the wall and increases in magnitude with reductions in drag. Similarly, with increasing drag reduction, the profile of the combined Reynolds and polymer shear stress exhibits a decrease in its maximum value that also moves farther from the wall. Correlations are presented that estimate the location and value of the maximum rms streamwise velocity and combined Reynolds and polymer shear stress. Over the range of DR investigated, these effects consistently exhibit approximately linear trends as a function of DR. The present measurements allow reconstruction of the mean momentum balance (MMB) for channel flow, which provides further insights regarding the physics described in the study by White et al. In particular, the present findings support a physical scenario in which the self-similar properties on the inertial domain identified from the leading order structure of the MMB begin to detectably and continuously vary for drag reductions less than 10%.

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

Kim

Sirviente

2005

Exp Fluids

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The presence of macromolecular polymer structures in a fully developed turbulent channel flow has been shown to substantially increase the drag reduction compared to non-structured polymer flows. This study presents a detailed analysis of experimental data obtained using laser Doppler velocimetry (LDV) to develop insights into the effects of the presence of macromolecular polymer structures on the turbulence characteristics of a channel flow. It is argued that polymer structures could contribute to minimizing the interaction between the inner and outer regions of the flow, which, in turn, can contribute to the modification of the coherent structure of the turbulence.

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Effect of macromolecular polymer structures on drag reduction in a turbulent channel flow

Cited by 17 publications

References 40 publications

Wall Versus Centerline Polymer Injection in Turbulent Channel Flows

Wall Versus Centerline Polymer Injection in Turbulent Channel Flows

Turbulence Production in the Low Polymer Drag Reduction Regime

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

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