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Viscosity

  • Nicolaas Westerhof
  • Nikolaos Stergiopulos
  • Mark I. M. Noble
  • Berend E. Westerhof
Chapter

Abstract

The definition of viscosity. Consider a fluid located between two parallel plates with distance h and velocity difference v. The shear force, F, divided by the contact area, A, between the liquid and the plate is the shear stress, F/A = τ. The shear rate is the difference in velocity between the different fluid layers thus the shear rate is γ = v/h. The ratio of shear stress and shear rate is the viscosity, η, and is a material property of the fluid. If the ratio of shear rate and shear stress is constant, as for plasma, we call the fluid Newtonian. Blood has a nonlinear relation between shear rate and shear stress.

Keywords

Shear Shear force Shear rate Blood viscosity Newtonian fluid 

References

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    Scott Blair GW, Spanner DC. An introduction to biorheology. Amsterdam: Elsevier Scientific Publishing; 1974.Google Scholar
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    Pries AR, Secomb TW, Gessner T, Sperandio MB, Gross JF, Gaehtgens P. Resistance to blood flow in microvessels in vivo. Circ Res. 1994;75:904–15.CrossRefPubMedGoogle Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2019

Authors and Affiliations

  • Nicolaas Westerhof
    • 1
  • Nikolaos Stergiopulos
    • 2
  • Mark I. M. Noble
    • 3
  • Berend E. Westerhof
    • 1
  1. 1.Department of Pulmonary Diseases, Amsterdam Cardiovascular SciencesVU University Medical CenterAmsterdamThe Netherlands
  2. 2.Laboratory of Hemodynamics and Cardiovascular TechnologyEcole Polytechnique Fédérale de Lausanne (EPFL), Institute of BioengineeringLausanneSwitzerland
  3. 3.Cardiovascular Medicine, Department of Medicine and TherapeuticsUniversity of AberdeenAberdeenUnited Kingdom

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