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Analytical Solutions for Simple Turbulent Shear Flows on a Basis of a Generalized Newton’s Law

In the presented article a generalization of Newton’s formula for the shear stress in a fluid is carried out by giving it a power-law form. After the introduction of the corresponding strain rate tensor, a generalization is made to the spatial case of flow and the rheological relation is presented i...

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Autores principales: Nikushchenko, Dmitry, Pavlovsky, Valery, Nikushchenko, Elena
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9415900/
https://www.ncbi.nlm.nih.gov/pubmed/36015565
http://dx.doi.org/10.3390/polym14163308
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author Nikushchenko, Dmitry
Pavlovsky, Valery
Nikushchenko, Elena
author_facet Nikushchenko, Dmitry
Pavlovsky, Valery
Nikushchenko, Elena
author_sort Nikushchenko, Dmitry
collection PubMed
description In the presented article a generalization of Newton’s formula for the shear stress in a fluid is carried out by giving it a power-law form. After the introduction of the corresponding strain rate tensor, a generalization is made to the spatial case of flow and the rheological relation is presented in tensor form. Depending on the power value in this rheological ratio, one can come either to a description of a laminar flow regime (in the form of Navier–Stokes equations), or to a description of the flow in turbulent regime. In the latter case, a set of differential equations with the no-slip boundary condition is specified, which is significantly different from that for the laminar flow regime, but which also allows one to obtain analytical solutions for simple shear flows and obtain the Blasius resistance law for the flow in a pipe. Therefore, the considered approach to solving problems of turbulent flows compares favorably with modern differential turbulence models. Solutions are given for simple shear flows of a fluid, when there is only one longitudinal component of the velocity, which depends on the transversal coordinate only. These solutions in terms of velocity profiles and resistance coefficients are in satisfactory agreement with the experimental data.
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spelling pubmed-94159002022-08-27 Analytical Solutions for Simple Turbulent Shear Flows on a Basis of a Generalized Newton’s Law Nikushchenko, Dmitry Pavlovsky, Valery Nikushchenko, Elena Polymers (Basel) Article In the presented article a generalization of Newton’s formula for the shear stress in a fluid is carried out by giving it a power-law form. After the introduction of the corresponding strain rate tensor, a generalization is made to the spatial case of flow and the rheological relation is presented in tensor form. Depending on the power value in this rheological ratio, one can come either to a description of a laminar flow regime (in the form of Navier–Stokes equations), or to a description of the flow in turbulent regime. In the latter case, a set of differential equations with the no-slip boundary condition is specified, which is significantly different from that for the laminar flow regime, but which also allows one to obtain analytical solutions for simple shear flows and obtain the Blasius resistance law for the flow in a pipe. Therefore, the considered approach to solving problems of turbulent flows compares favorably with modern differential turbulence models. Solutions are given for simple shear flows of a fluid, when there is only one longitudinal component of the velocity, which depends on the transversal coordinate only. These solutions in terms of velocity profiles and resistance coefficients are in satisfactory agreement with the experimental data. MDPI 2022-08-14 /pmc/articles/PMC9415900/ /pubmed/36015565 http://dx.doi.org/10.3390/polym14163308 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Nikushchenko, Dmitry
Pavlovsky, Valery
Nikushchenko, Elena
Analytical Solutions for Simple Turbulent Shear Flows on a Basis of a Generalized Newton’s Law
title Analytical Solutions for Simple Turbulent Shear Flows on a Basis of a Generalized Newton’s Law
title_full Analytical Solutions for Simple Turbulent Shear Flows on a Basis of a Generalized Newton’s Law
title_fullStr Analytical Solutions for Simple Turbulent Shear Flows on a Basis of a Generalized Newton’s Law
title_full_unstemmed Analytical Solutions for Simple Turbulent Shear Flows on a Basis of a Generalized Newton’s Law
title_short Analytical Solutions for Simple Turbulent Shear Flows on a Basis of a Generalized Newton’s Law
title_sort analytical solutions for simple turbulent shear flows on a basis of a generalized newton’s law
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9415900/
https://www.ncbi.nlm.nih.gov/pubmed/36015565
http://dx.doi.org/10.3390/polym14163308
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