Barthelemy Thibaud, Simon Mendez, Franck Nicoud
A 3D bicuspid venous valve model is used to investigate the biomechanical role of leaflet buckling in achieving efficient, low-pressure opening. The model is parameterized to represent the femoral vein, common femoral vein, and popliteal vein, with sizes and flow rates scaled to match in vivo conditions. Using a body-fitted numerical method with semi-implicit predictor-corrector coupling, we demonstrate that leaflet buckling enables opening through low-energy bending rather than energetically costly elastic stretching. This design ensures a maximum opening pressure loss of 42 Pa in the cases tested, significantly lower than previously reported values and compatible with the physiologically observed pressure loss, highlighting the importance of excess surface area in minimizing flow resistance while maintaining valve competence. Even with thickened leaflets and the resulting reduced effective opening area, the pressure loss for this model remains largely below physiological pressure loss compared to other numerical studies on venous valves. Finally, complex downstream flow patterns suggest potential interactions with proximal valve dynamics, even under bed-rest conditions.