Hamidreza Toloueinasab - Department of Mechanical Engineering, University of Tabriz, Tabriz;
Seyed Esmail Razavi - Department of Mechanical Engineering, University of Tabriz, Tabriz;

Veins inside the human body return blood from differentbody organs to the heart. at lower body parts, veinsinclude valves known as venous valves whose duty is toprevent the reverse flow of blood inside the vein. Anyabnormalities among the leaflets of these valves causevenous valve insufficiency and in the long-term varicoseveins in the legs. Hemodynamical and mechanicalproperties of the blood flow and vein wall play animportant role in causing such complications such thatstudying them is necessary to identify possible spots forthrombus or clot formation. In the present study, twodimensionalnumerical models of the geometry includingpopliteal vein, venous valve and blood flow are simulatedand investigated using the finite element method.Governing equations consist of continuity, Navier-stokesequations, non-Newtonian blood model, structure motionequation and fluid-solid interaction equations. Resultsinclude blood flow velocity and pressure fields, andstress and strain on the elastic tissue with respect to valveinsufficiency. Numerical results indicate that the reverseflow (reflux) duration increases with the gap width. itexceeds half of the period for the valves with the gapexceeding ۵% of its diameter and is classified as strongreflux. Defined correlation between the blood flowpatterns and the valve geometry can contribute tounderstanding the details of the venous valve mechanicsand developing new techniques for surgical correction ofits insufficiency.

Venous valve, Navier-Stokes Equations,Fluid-Solid Interaction, Computational Fluid Dynamics,Non-Newtonian Fluid