De Hart J, Peters G W, Schreurs P J, Baaijens F P
Department of Mechanical Engineering, Eindhoven University of Technology, The Netherlands.
J Biomech. 2000 Sep;33(9):1079-88. doi: 10.1016/s0021-9290(00)00068-3.
Failure of synthetic heart valves is usually caused by tearing and calcification of the leaflets. Leaflet fiber-reinforcement increases the durability of these valves by unloading the delicate parts of the leaflets, maintaining their physiological functioning. The interaction of the valve with the surrounding fluid is essential when analyzing its functioning. However, the large differences in material properties of fluid and structure and the finite motion of the leaflets complicate blood-valve interaction modeling. This has, so far, obstructed numerical analyses of valves operating under physiological conditions. A two-dimensional fluid-structure interaction model is presented, which allows the Reynolds number to be within the physiological range, using a fictitious domain method based on Lagrange multipliers to couple the two phases. The extension to the three-dimensional case is straightforward. The model has been validated experimentally using laser Doppler anemometry for measuring the fluid flow and digitized high-speed video recordings to visualize the leaflet motion in corresponding geometries. Results show that both the fluid and leaflet behaviour are well predicted for different leaflet thicknesses.
人造心脏瓣膜的失效通常是由瓣叶撕裂和钙化引起的。瓣叶纤维增强通过减轻瓣叶脆弱部分的负荷,维持其生理功能,从而提高了这些瓣膜的耐用性。在分析瓣膜功能时,瓣膜与周围流体的相互作用至关重要。然而,流体和结构的材料特性存在巨大差异,且瓣叶的有限运动使血液-瓣膜相互作用建模变得复杂。到目前为止,这阻碍了对在生理条件下运行的瓣膜进行数值分析。本文提出了一种二维流固耦合模型,该模型使用基于拉格朗日乘子的虚拟域方法来耦合两相,从而使雷诺数处于生理范围内。向三维情况的扩展很简单。该模型已通过实验验证,使用激光多普勒测速仪测量流体流动,并通过数字化高速视频记录来可视化相应几何形状中的瓣叶运动。结果表明,对于不同的瓣叶厚度,流体和瓣叶的行为都能得到很好的预测。