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Numerical simulations of Carreau‐model fluid flows past a circular cylinder
Author(s) -
Ohta Mitsuhiro,
Toyooka Takashi,
Matsukuma Yosuke
Publication year - 2020
Publication title -
asia‐pacific journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.348
H-Index - 35
eISSN - 1932-2143
pISSN - 1932-2135
DOI - 10.1002/apj.2527
Subject(s) - carreau fluid , reynolds number , mechanics , dilatant , shear thinning , lattice boltzmann methods , non newtonian fluid , cylinder , viscosity , materials science , mathematics , physics , turbulence , thermodynamics , geometry
Numerical simulations of shear‐thinning and shear‐thickening fluid flows past a circular cylinder are performed using a lattice Boltzmann method. In this study, the property of shear‐thinning and shear‐thickening fluids is expressed by the Carreau model. We focus on the definition of an effective (representative) Reynolds number for describing the flow of shear‐thinning and shear‐thickening fluids past a circular cylinder. The fluid flows and viscosity profiles are clearly shown for fluids flowing across a circular cylinder depending on the Reynolds and Carreau numbers and the power index. A large value of Carreau number lead to the formation of low‐viscosity regions for shear‐thinning and high‐viscosity regions for shear‐thickening around a circular cylinder. Meanwhile, the change in the viscosity around the cylinder is not remarkable for a small Carreau number. The formulation of the effective Reynolds number defined using effective shear rate and viscosity is proposed in order to organize and understand the flow of Carreau‐model fluids across a circular cylinder. The effective Reynolds number counseled in this study allows one to completely describe the flow state of Carreau‐model fluids past a circular cylinder on an equal footing with Newtonian fluid flows. The usefulness of the effective Reynolds numbers is discussed, and the feature of Carreau‐model fluid flows past a circular cylinder is considered in terms of the effective Reynolds number.