Complex Flow Patterns in Compressible Viscoelastic Liquids: Blood Flow Through a Compliant Aorta

In viscoelastic liquids, molecules are prone to spatial and temporal ordering. At equilibrium, the collective motions are rare events and their timespan is short. In flowing liquids, the propensity for ordering increases, and once molecular assemblies are formed, they trap a measurable amount of energy. The working hypothesis here is that the ordering phenomena are linked to microinertia forces, where the angular motion enables the collective response of molecules, pure shear supports the irrotational flow, and pressure perturbations aid the thermal fluctuations. The study is solely focused on the mechanistic aspect of the liquid's behavior. In the second part of the article, the model is implemented into a numerical code, where Lagrangian cells are subjected to Eulerian motions. The concept is applied to a medically relevant problem of the blood flow through a compliant aorta decorated with a plaque deposit. We have shown that the flow compressibility and the aorta viscoelasticity are among the key factors responsible for the plaque rupture. It should be stated that plaque rupture is the cause of most heart attacks worldwide.