Resonance of vortex in blood flow through stenosed tube

It is well known that the fluid dynamics of arterial blood flow play an important role in arterial disease. Periodic blood flow through a stenosed tube and a locally expanded tube was analyzed numerically. The fluid is assumed to be non-Newtonian, and the flow is assumed to be periodic, incompressible and axisymmetric. It is found that the vortex downstream of stenosis or expansion is strongest at a certain frequency, which is called resonance of vortex. The flow pattern, separated region and the distributions of pressure and shear stress at the wall are obtained. The results show that the resonance of vortex, which has great influence on the physical quantity of flow at the wall, occurs in both tubes. The mechanism of the resonance of vortex can be explained by a balance of forces between pressure and friction at the wall.