Modelling the new stress for improved drag reduction predictions of viscoelastic pipe flow

Cruz, D. O. A.; Pinho, F.T.; Resende, Pedro

doi:10.1016/j.jnnfm.2004.05.004

Cited by 43 publications

(69 citation statements)

References 20 publications

(50 reference statements)

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“…The rather poor agreement between numerical results and experimental data for certain polymer solutions 22,23) may have simply arisen because the fluid under investigation does not perfectly obey the modified GNF rheological model as proposed by Pinho. 21) Another explanation for the abovementioned discrepancy may lie in the fact that the Nagano-…”

Section: 23)mentioning

confidence: 96%

“…Cruz et al 23) managed to predict, for the first time, the level of the huge drag reduction which is observed in turbulent pipe flows of dilute polymer solutions. Their prediction for the friction factor is in good quantitative agreement with experimental data, but, there certain polymer solutions for…”

Section: Newtonian Fluidsmentioning

confidence: 99%

“…In this equation, C m is a standard parameter in k-e models with a value which depends on the turbulence model selected for the analysis (to be introduced shortly), A 2 is a constant equal to 0.45 which is deemed to be universal, at least, for Newtonian fluids 21) , and m and B are related to the rheology and flow kinematics as with A e being a parameter which quantifies the ratio between the fluctuating strain and shear rates. 23 …”

Section: The Direct Problemmentioning

confidence: 99%

“…It is to be noted that, y + is the wall coordinate defined by y , and Cruz et al 23) stressed that the correct strategy for evaluating this parameter is through an inverse scheme. In practice, however, they relied on a trial-and-error method for its determination.…”

Section: The Direct Problemmentioning

confidence: 99%

“…Due to lack of sufficient experimental data, Cruz et al 23) used this ratio as an adjusting parameter which was determined through a trial-and-error method to be equal to 3. In the present work, C 0 , too, will be determined through an inverse method.…”

Section: The Direct Problemmentioning

confidence: 99%

See 4 more Smart Citations

On the Use of Inverse Methods to Parameter Estimation in Turbulent Pipe Flows of Drag Reducing Polymers

Mehrabadi

Sadeghy

Hakkaki-Fard

et al. 2008

J. Soc. Rheol., Jpn

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This article investigates the applicability of inverse methods in estimating the best values to be assigned to certain parameters which appear in turbulent flow studies of dilute polymer solutions in circular pipes. These parameters naturally arise when the Nagano-Hishida low-Re, k-e model is combined with a special form of the Generalized Newtonian Fluid model modified in such a way that it could account for the elasticity of dilute polymer solutions. This multi-objective problem is treated by a positively weighted convex sum of the objectives. Then the procedure is followed by a well-known Gauss-Newton nonlinear optimization method for optimizing model parameters in order to better predict the drag reduction phenomenon using polymeric additives. Parameter optimization relies on the availability of experimental data for the velocity profiles, friction factor, and turbulence kinetic energy for at least one concentration of a given polymer. It is shown that using these optimized parameters, it is possible to predict with more accuracy the amount of drag reduction achievable using a given polymeric additive. It is also shown that these parameters may neither work for other concentrations of the same polymer nor necessarily for any concentration of any other polymer, inferring that for non-Newtonian fluids these parameters are not at all universal.

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Section: 23)mentioning

confidence: 96%

Section: Newtonian Fluidsmentioning

confidence: 99%

Section: The Direct Problemmentioning

confidence: 99%

Section: The Direct Problemmentioning

confidence: 99%

Section: The Direct Problemmentioning

confidence: 99%

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On the Use of Inverse Methods to Parameter Estimation in Turbulent Pipe Flows of Drag Reducing Polymers

Mehrabadi

Sadeghy

Hakkaki-Fard

et al. 2008

J. Soc. Rheol., Jpn

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Numerical Simulation of Surfactant Drag Reduction

Wei

et al. 2012

Turbulent Drag Reduction by Surfactant Additives

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Development of a Method to Evaluate the Performance of Aqueous Polymer Solutions as Drag Reduction Agents in Bench Scale

Figueiredo

Almeida

Costa

et al. 2006

Macromolecular Symposia

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Summary: This work describes a method to evaluate, in reduced scale, the performance of polymer samples as drag reduction agents in aqueous solutions. To measure the pressure drop in a turbulent regime, a specially adapted capillary viscosimeter was used, with reduced dimensions adapted to produce the desired regime and adequate pressure measurement points. To verify the technique's reliability, samples of polyacrylamide were synthesized with different molar masses, by varying the quantity of the polymerization initiator. The molar masses obtained were determined by size exclusion chromatography (SEC). The efficiency of the polymer as a drag reducer, as expected, increased as the molar mass increased, which validates the use of this method to study the drag reduction properties of polymer materials in aqueous solutions.

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Modelling the new stress for improved drag reduction predictions of viscoelastic pipe flow

Cited by 43 publications

References 20 publications

On the Use of Inverse Methods to Parameter Estimation in Turbulent Pipe Flows of Drag Reducing Polymers

On the Use of Inverse Methods to Parameter Estimation in Turbulent Pipe Flows of Drag Reducing Polymers

Numerical Simulation of Surfactant Drag Reduction

Development of a Method to Evaluate the Performance of Aqueous Polymer Solutions as Drag Reduction Agents in Bench Scale

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