Substantial differences in flow behavior and shear gradients were found between Newtonian and non-Newtonian fluids, and between elastic and rigid walls, particularly behind the bifurcation.
In vitro modeling shows that non-Newtonian fluid properties and wall elasticity significantly alter flow behavior and shear gradients at arterial bifurcations, which may contribute to blood cell damage.
To study the fundamentals of hemodynamics in arteries, the flow parameters: pulsatility, elasticity and non-Newtonian viscoelasticity were considered in detail in a 90 degrees-T-bifurcation of a rigid and elastic model. The velocity distribution 2.5 mm behind the bifurcation in the straight tube was measured with a laser-Doppler-anemometer. The fluid used was an aqueous glycerine solution and a viscoelastic Separan mixture. Flow visualization studies were done with a sheet of laser light in the plane of the bifurcation. The velocity distribution was measured for both steady and pulsatile flows with a laser-Doppler-anemometer in a backward scattered way. From the velocity measurements the shear gradients were calculated. Substantial differences were found in the flow behavior of Newtonian and non-Newtonian fluids, especially behind the bifurcation in the main tube, where secondary flows and flow separation started. Also, differences due to the elastic and rigid wall could be seen. Very high shear gradients were found in the flow between main flow and the separation zone which can lead to a damage of the blood cells.
Ku et al. (Fri,) conducted a other in Hemodynamics in arteries. Non-Newtonian viscoelastic fluid and elastic wall model vs. Newtonian fluid and rigid wall model was evaluated on Velocity distribution and shear gradients. Substantial differences in flow behavior and shear gradients were found between Newtonian and non-Newtonian fluids, and between elastic and rigid walls, particularly behind the bifurcation.