Distinguishing between Newtonian and non Newtonian character of blood flow in vascular bifurcations and bends

S.V. Frolov, D. Liepsch, S.V. Sindeev

Abstract: Numerous computational and experimental flow studies in models of the human circulatory system have been published over the last three decades, especially concentrating on bends and bifurcations where velocity fluctuations are observed. Many authors use assumptions for the calculations such as steady instead of unsteady flow, or neglect the wall elasticity. The non-Newtonian flow behaviour of blood is often ignored, because in many textbooks the blood flow can be considered as a Newtonian fluid in large arteries. Fundamental fluid mechanics definitions such as laminar and turbulent flow are imprecise, unclear or sometimes even wrong. This paper shows clearly the flow behaviour in arterial models. No turbulent flow can be seen, only a nominal laminar or transitional flow exists in our blood circulatory system. The expression “turbulent” flow used today in many papers is incorrect and misleading. The flow behaviours of a Newtonian and a non-Newtonian fluid are significantly different at bifurcations and branches where recirculation zones are created at special flow-rate ratios. These fluid mechanics basics are important to understand the influence of blood flow in arteries forming thromboses and creating stenoses.


Series on Biomechanics, Vol.32, No.2 (2018), 3-11

Keywords: Cardiovascular system; experimental setup; flow visualization; hemodynamics; non-Newtonian fluid

Date published: 2018-08-20