Le Trung Bao, Sotiropoulos Fotis
St. Anthony Falls Laboratory, Department of Civil Engineering, University of Minnesota, Minneapolis, MN, USA.
Eur J Mech B Fluids. 2012 Sep;35:20-24. doi: 10.1016/j.euromechflu.2012.01.013.
We study the formation of the mitral vortex ring during early diastolic filling in a patient-specific left ventricle using direct numerical simulation. The geometry of the left ventricle is reconstructed from Magnetic Resonance Imaging (MRI). The heart wall motion is modeled by a cell-based activation methodology, which yields physiologic kinematics with heart rate equal to 52 beats per minute. We show that the structure of the mitral vortex ring consists of the main vortex ring and trailing vortex tubes, which originate at the heart wall. The trailing vortex tubes play an important role in exciting twisting circumferential instability modes of the mitral vortex ring. At the end of diastole, the vortex ring impinges on the wall and the intraventricular flow transitions to a weak turbulent state. Our results can be used to help interprete and analyze three-dimensional in-vivo flow measurements obtained with MRI.
我们使用直接数值模拟方法研究了特定患者左心室舒张早期充盈过程中二尖瓣涡环的形成。左心室的几何形状由磁共振成像（MRI）重建而来。心脏壁运动采用基于细胞的激活方法进行建模，该方法可产生心率为每分钟52次的生理运动学特征。我们发现二尖瓣涡环的结构由主涡环和起源于心脏壁的尾涡管组成。尾涡管在激发二尖瓣涡环的扭转周向不稳定模式中起着重要作用。在舒张末期，涡环撞击心室壁，心室内流动转变为弱湍流状态。我们的结果可用于帮助解释和分析通过MRI获得的三维体内血流测量结果。
