Impact of Addition of a Newtonian Solvent to a Giesekus Fluid: Analytical Determination of Flow Rate in Plane Laminar Motion

In this study, the influence of the presence of a Newtonian solvent on the flow of a Giesekus fluid in a plane channel or fracture is investigated with a focus on the determination of the flow rate for an assigned external pressure gradient. The pressure field is nonlinear due to the presence of the...

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Main Authors: Irene Daprà, Giambattista Scarpi, Vittorio Di Federico
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Fluids
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Online Access:https://www.mdpi.com/2311-5521/10/1/1
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author Irene Daprà
Giambattista Scarpi
Vittorio Di Federico
author_facet Irene Daprà
Giambattista Scarpi
Vittorio Di Federico
author_sort Irene Daprà
collection DOAJ
description In this study, the influence of the presence of a Newtonian solvent on the flow of a Giesekus fluid in a plane channel or fracture is investigated with a focus on the determination of the flow rate for an assigned external pressure gradient. The pressure field is nonlinear due to the presence of the normal transverse stress component. As expected, the flow rate per unit width <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mrow><mi>Q</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></semantics></math></inline-formula> is larger than for a Newtonian fluid and decreases as the solvent increases. It is strongly dependent on the viscosity ratio <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>ε</mi></mrow></semantics></math></inline-formula> (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0</mn><mo>≤</mo><mi>ε</mi><mo>≤</mo><mn>1</mn></mrow></semantics></math></inline-formula>), the dimensionless mobility parameter <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>β</mi><mo> </mo></mrow></semantics></math></inline-formula>(<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0</mn><mo>≤</mo><mi>β</mi><mo>≤</mo><mn>1</mn></mrow></semantics></math></inline-formula>) and the Deborah number <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>D</mi><mi>e</mi></mrow></semantics></math></inline-formula>, the dimensionless driving pressure gradient. The degree of dependency is notably strong in the low range of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>ε</mi></mrow></semantics></math></inline-formula>. Furthermore, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mrow><mi>Q</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></semantics></math></inline-formula> increases with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>D</mi><mi>e</mi></mrow></semantics></math></inline-formula> and tends to a constant asymptotic value for large <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>D</mi><mi>e</mi></mrow></semantics></math></inline-formula>, subject to the limitation of laminar flow. When the mobility factor <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>β</mi></mrow></semantics></math></inline-formula> is in the range <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mfenced open="[" close="]" separators="|"><mrow><mn>0.5</mn><mo>÷</mo><mn>1</mn></mrow></mfenced></mrow></semantics></math></inline-formula>, there is a minimum value of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>ε</mi><mo> </mo></mrow></semantics></math></inline-formula> to obtain an assigned value of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>D</mi><mi>e</mi></mrow></semantics></math></inline-formula>. The ratio <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>U</mi></mrow><mrow><mi>N</mi></mrow></msub><mo>/</mo><mi>U</mi></mrow></semantics></math></inline-formula> between Newtonian and actual mean velocity depends only on the product <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msqrt><mi>β</mi></msqrt><mi>D</mi><mi>e</mi></mrow></semantics></math></inline-formula>, as for other non-Newtonian fluids.
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spelling doaj-art-f14b6e179975493e87d7c7a7adbf778e2025-01-24T13:32:32ZengMDPI AGFluids2311-55212024-12-01101110.3390/fluids10010001Impact of Addition of a Newtonian Solvent to a Giesekus Fluid: Analytical Determination of Flow Rate in Plane Laminar MotionIrene Daprà0Giambattista Scarpi1Vittorio Di Federico2Department of Civil, Chemical, Environmental, and Materials Engineering, University of Bologna, 40136 Bologna, ItalyDepartment of Civil, Chemical, Environmental, and Materials Engineering, University of Bologna, 40136 Bologna, ItalyDepartment of Civil, Chemical, Environmental, and Materials Engineering, University of Bologna, 40136 Bologna, ItalyIn this study, the influence of the presence of a Newtonian solvent on the flow of a Giesekus fluid in a plane channel or fracture is investigated with a focus on the determination of the flow rate for an assigned external pressure gradient. The pressure field is nonlinear due to the presence of the normal transverse stress component. As expected, the flow rate per unit width <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mrow><mi>Q</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></semantics></math></inline-formula> is larger than for a Newtonian fluid and decreases as the solvent increases. It is strongly dependent on the viscosity ratio <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>ε</mi></mrow></semantics></math></inline-formula> (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0</mn><mo>≤</mo><mi>ε</mi><mo>≤</mo><mn>1</mn></mrow></semantics></math></inline-formula>), the dimensionless mobility parameter <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>β</mi><mo> </mo></mrow></semantics></math></inline-formula>(<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0</mn><mo>≤</mo><mi>β</mi><mo>≤</mo><mn>1</mn></mrow></semantics></math></inline-formula>) and the Deborah number <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>D</mi><mi>e</mi></mrow></semantics></math></inline-formula>, the dimensionless driving pressure gradient. The degree of dependency is notably strong in the low range of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>ε</mi></mrow></semantics></math></inline-formula>. Furthermore, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mrow><mi>Q</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></semantics></math></inline-formula> increases with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>D</mi><mi>e</mi></mrow></semantics></math></inline-formula> and tends to a constant asymptotic value for large <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>D</mi><mi>e</mi></mrow></semantics></math></inline-formula>, subject to the limitation of laminar flow. When the mobility factor <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>β</mi></mrow></semantics></math></inline-formula> is in the range <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mfenced open="[" close="]" separators="|"><mrow><mn>0.5</mn><mo>÷</mo><mn>1</mn></mrow></mfenced></mrow></semantics></math></inline-formula>, there is a minimum value of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>ε</mi><mo> </mo></mrow></semantics></math></inline-formula> to obtain an assigned value of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>D</mi><mi>e</mi></mrow></semantics></math></inline-formula>. The ratio <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>U</mi></mrow><mrow><mi>N</mi></mrow></msub><mo>/</mo><mi>U</mi></mrow></semantics></math></inline-formula> between Newtonian and actual mean velocity depends only on the product <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msqrt><mi>β</mi></msqrt><mi>D</mi><mi>e</mi></mrow></semantics></math></inline-formula>, as for other non-Newtonian fluids.https://www.mdpi.com/2311-5521/10/1/1Giesekus modelflow rateviscoelastic fluidNewtonian solventanalytical solutionplane flow
spellingShingle Irene Daprà
Giambattista Scarpi
Vittorio Di Federico
Impact of Addition of a Newtonian Solvent to a Giesekus Fluid: Analytical Determination of Flow Rate in Plane Laminar Motion
Fluids
Giesekus model
flow rate
viscoelastic fluid
Newtonian solvent
analytical solution
plane flow
title Impact of Addition of a Newtonian Solvent to a Giesekus Fluid: Analytical Determination of Flow Rate in Plane Laminar Motion
title_full Impact of Addition of a Newtonian Solvent to a Giesekus Fluid: Analytical Determination of Flow Rate in Plane Laminar Motion
title_fullStr Impact of Addition of a Newtonian Solvent to a Giesekus Fluid: Analytical Determination of Flow Rate in Plane Laminar Motion
title_full_unstemmed Impact of Addition of a Newtonian Solvent to a Giesekus Fluid: Analytical Determination of Flow Rate in Plane Laminar Motion
title_short Impact of Addition of a Newtonian Solvent to a Giesekus Fluid: Analytical Determination of Flow Rate in Plane Laminar Motion
title_sort impact of addition of a newtonian solvent to a giesekus fluid analytical determination of flow rate in plane laminar motion
topic Giesekus model
flow rate
viscoelastic fluid
Newtonian solvent
analytical solution
plane flow
url https://www.mdpi.com/2311-5521/10/1/1
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AT vittoriodifederico impactofadditionofanewtoniansolventtoagiesekusfluidanalyticaldeterminationofflowrateinplanelaminarmotion