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JOURNALS // Vestnik of Saint Petersburg University. Mathematics. Mechanics. Astronomy // Archive

Vestnik of Saint Petersburg University. Mathematics. Mechanics. Astronomy, 2022 Volume 9, Issue 2, Pages 338–345 (Mi vspua13)

MECHANICS

Power-law generalization of Newton's formula for shear stress in a liquid in the form of a tensor rheological relation

V. A. Pavlovsky

St Petersburg State Marine Technical University, 3, Lotsmanskaya ul., St Petersburg, 190121, Russian Federation

Abstract: A generalization of Newton's formula for the shear stress in a fluid is carried out by giving it a power-law form and the corresponding rheological relation is written in tensor form. Depending on the exponent in this rheological ratio, one can come to a description of either a laminar or turbulent flow regime. In the latter case, there is a system of differential equations with the no-slip boundary condition. The proposed system of equations for turbulent fluid motion can be useful, at least, for obtaining preliminary, estimated characteristics of turbulent flow before starting numerical modeling using modern differential turbulence models. For some values of the exponent, this system can be used to describe the behavior of power-law fluids, as well as fluids with small additives of polymers in the manifestation of the Toms effect.

Keywords: power formulas, generalization of Newton's formula, Blasius formula, stress tensor, differential equations of turbulent flow, analytical solutions.

UDC: 532.517.4

MSC: 76F02

Received: 03.03.2021
Revised: 18.11.2021
Accepted: 02.12.2021

DOI: 10.21638/spbu01.2022.213


 English version:
Vestnik St. Petersburg University, Mathematics, 2022, 9:2, 338–345


© Steklov Math. Inst. of RAS, 2024