Borazjani Iman, Ge Liang, Le Trung, Sotiropoulos Fotis
Department of Mechanical and Aerospace Engineering, SUNY University at Bu alo, NY, USA.
Comput Fluids. 2013 Apr 1;77:76-96. doi: 10.1016/j.compfluid.2013.02.017.
We develop an overset-curvilinear immersed boundary (overset-CURVIB) method in a general non-inertial frame of reference to simulate a wide range of challenging biological flow problems. The method incorporates overset-curvilinear grids to efficiently handle multi-connected geometries and increase the resolution locally near immersed boundaries. Complex bodies undergoing arbitrarily large deformations may be embedded within the overset-curvilinear background grid and treated as sharp interfaces using the curvilinear immersed boundary (CURVIB) method (Ge and Sotiropoulos, Journal of Computational Physics, 2007). The incompressible flow equations are formulated in a general non-inertial frame of reference to enhance the overall versatility and efficiency of the numerical approach. Efficient search algorithms to identify areas requiring blanking, donor cells, and interpolation coefficients for constructing the boundary conditions at grid interfaces of the overset grid are developed and implemented using efficient parallel computing communication strategies to transfer information among sub-domains. The governing equations are discretized using a second-order accurate finite-volume approach and integrated in time via an efficient fractional-step method. Various strategies for ensuring globally conservative interpolation at grid interfaces suitable for incompressible flow fractional step methods are implemented and evaluated. The method is verified and validated against experimental data, and its capabilities are demonstrated by simulating the flow past multiple aquatic swimmers and the systolic flow in an anatomic left ventricle with a mechanical heart valve implanted in the aortic position.
我们在一般非惯性参考系中开发了一种重叠曲线浸入边界（overset-CURVIB）方法，以模拟各种具有挑战性的生物流动问题。该方法采用重叠曲线网格来有效处理多连通几何形状，并提高浸入边界附近的局部分辨率。经历任意大变形的复杂物体可以嵌入重叠曲线背景网格中，并使用曲线浸入边界（CURVIB）方法（Ge和Sotiropoulos，《计算物理杂志》，2007年）将其视为尖锐界面。不可压缩流动方程在一般非惯性参考系中建立，以提高数值方法的整体通用性和效率。开发并实施了高效搜索算法，以识别需要消隐的区域、供体细胞以及用于在重叠网格的网格界面处构建边界条件的插值系数，并使用高效的并行计算通信策略在子域之间传输信息。控制方程使用二阶精确有限体积法离散，并通过高效的分数步方法进行时间积分。实施并评估了各种用于在适合不可压缩流分数步方法的网格界面处确保全局守恒插值的策略。该方法通过与实验数据进行验证和确认，并通过模拟多个水生游泳者周围的流动以及在主动脉位置植入机械心脏瓣膜的解剖左心室中的收缩期流动来展示其能力。
