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Turbulence

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

Abstract

In laminar flow blood particles remain in a single layer, while in turbulent flow the particles move erratically between layers. Turbulent flow is less efficient than laminar flow, i.e., a relatively larger pressure difference is required for the same amount of flow. The Reynolds number is a dimensionless number (no units) characterizing the flow. In a straight vessel, when the Reynolds number exceeds the critical value of 2200 flow becomes turbulent. Below the critical Reynolds number flow is laminar. In general, flow in the arterial system is laminar. In the aorta when cardiac output is large, as during exercise, flow can be turbulent. Flow distal to stenoses and stenotic valves is turbulent. Flows in vascular access grafts in hemodialysis patients can also be very high leading to turbulence.

Keywords

Reynolds number Stenosis Non-laminar flow 

Reference

  1. 1.
    Munson BR, Young DF, Okiishi TH. Fundamentals of fluid mechanics. New York: Wiley; 1994.Google 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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