Peristalsis is a common motion in various biological systems, especially the upper urinary tract, where it plays a pivotal role in conveying urine from the kidneys to the bladder. Using computational fluid dynamics, this study aims to investigate the effect of various peristaltic parameters on the motion of an obstacle through a two-dimensional ureter. Methodologically, Incompressible Navier–Stokes equations were utilized as the fluid domain's governing equations, and the Dynamic Mesh method (DM) was employed to simulate the peristaltic and obstacle motion. The peristaltic motion was modeled by a sinusoidal contraction wave propagating alongside the ureter at the physiological speed, and the motion of the obstruction through the ureter, which is caused by the fluid forces applied on its surface, was explored using the equation of Newton's second law. Various test cases of different shapes and sizes were supposed as kidney stones to understand the influence of the peristalsis properties on the stone removal process. The results show that the motion of the kidney stone is highly influenced by the gradient pressure force applied to its surface in the fluid domain. Moreover, investigating the effects of the peristaltic physical properties on the obstacle's motion indicates that the stone's motion is dependent on these parameters. Furthermore, this analysis provides insight into the peristaltic motion effects, assisting physicians in developing new medicines to facilitate the kidney stone removal process based on its shape and size.

中文翻译：

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使用动态网格方法对人类输尿管中的障碍物运动进行数值分析

蠕动是各种生物系统中的常见运动，尤其是上尿路，它在将尿液从肾脏输送到膀胱的过程中发挥着关键作用。本研究旨在利用计算流体动力学研究各种蠕动参数对障碍物通过二维输尿管运动的影响。方法上，采用不可压缩纳维-斯托克斯方程作为流体域的控制方程，并采用动态网格法（DM）来模拟蠕动和障碍运动。蠕动运动是通过以生理速度沿输尿管传播的正弦收缩波来模拟的，并且使用牛顿第二定律方程探索了由施加在输尿管表面的流体力引起的通过输尿管的阻塞运动。各种不同形状和大小的测试用例被假设为肾结石，以了解蠕动特性对结石清除过程的影响。结果表明，肾结石的运动很大程度上受到流体域中施加到其表面的梯度压力的影响。此外，研究蠕动物理特性对障碍物运动的影响表明，石头的运动取决于这些参数。此外，该分析还提供了对蠕动运动效应的深入了解，帮助医生开发新药物，以根据肾结石的形状和大小促进肾结石的清除过程。