Stevenson D M, Yoganathan A P
J Biomech. 1985;18(12):899-907. doi: 10.1016/0021-9290(85)90034-x.
A numerical simulation model and technique are described to simulate steady turbulent blood flow through trileaflet tissue valves of varying degrees of stenosis. The aortic trileaflet tissue valve design was chosen as the subject of this study, since it is the only popular valve in current clinical use which is approximately axisymmetric. An axisymmetric geometry is computationally more convenient since it involves only two dimensional equations. The geometry and dimensions of the aorta were designed from angiographic studies and measurements made from cadavers. The valve dimensions were obtained from tissue leaflet photography studies conducted on tissue bioprostheses of varying degrees of stenosis. The non-rectangular nature of this valve necessitated the use of a body conforming grid. Thompson's method coupled with a Chimera grid system was chosen for this purpose. The Chimera grid was used to avoid a grid with highly skewed cells. Turbulence was simulated by using the kappa-epsilon model with the wall function method. This decision was made after comparing the kappa-epsilon model's performance with that of lower order models, and after considering the increased computer time requirements and decreased stability of more complex models, such as the Reynolds stress model. The results of the study which are very encouraging and compare favorably with in vitro experimental data, are described in Part II of the paper.
本文描述了一种数值模拟模型和技术，用于模拟血液在不同狭窄程度的三叶组织瓣膜中稳定的湍流流动。本研究选择主动脉三叶组织瓣膜作为研究对象，因为它是目前临床使用中唯一近似轴对称的常用瓣膜。轴对称几何形状在计算上更为方便，因为它只涉及二维方程。主动脉的几何形状和尺寸是根据血管造影研究和对尸体的测量设计的。瓣膜尺寸是通过对不同狭窄程度的组织生物假体进行组织瓣叶摄影研究获得的。这种瓣膜的非矩形性质使得必须使用贴合物体的网格。为此选择了汤普森方法与嵌套网格系统相结合。使用嵌套网格是为了避免出现具有高度扭曲单元的网格。通过使用κ-ε模型和壁面函数法来模拟湍流。这一决定是在将κ-ε模型的性能与低阶模型的性能进行比较之后，并且在考虑到更复杂模型（如雷诺应力模型）增加的计算机时间需求和降低的稳定性之后做出的。本研究结果非常令人鼓舞，与体外实验数据相比具有优势，将在本文第二部分进行描述。
