The mechanics of bile flow in the biliary system plays an important role in studying bile stasis and gallstone formation. Bile duct stricture is an abnormal phenomenon that refers to the bile duct getting smaller or narrower. The main objective of this study is to study the influence of stricture on bile flow dynamics using numerical methods. We employed a numerical Computational Fluid Dynamics model of the bile flow within a strictured hepatic duct. We studied and compared the influence of stricture severity, stricture length, eccentricity, and bile flow property on the bile flow dynamics. The bile flow velocity, pressure distribution, pressure drop, and wall shear stress are provided in detail. The stricture alters the normal bile flow pattern and increases flow resistance. At the location upstream and downstream of the stricture, bile flow slows down. In the area of the stricture throat, bile flow is accelerated, and recirculation forms behind the stricture. The maximum pressure drop of the biliary system increases with the stricture length. The eccentricity makes the flow deflect away from the duct's centerline. The behavior of the deflected flow is significantly altered downstream of the stricture. Such bile flow behavior as deceleration and recirculation may lead to cholestasis. Stricture alters bile flow in the biliary tract, causing changes in biliary hydrodynamic indexes, which could potentially serve as an omen for gallstone formation and other related diseases. The consideration of the bile duct stricture could lead to better patient stratification.

中文翻译：

---

狭窄胆管内胆汁流动动力学的分析和数值研究

胆道系统中胆汁流动的力学在研究胆汁淤滞和胆结石形成中起着重要作用。胆管狭窄是指胆管变小或变窄的异常现象。本研究的主要目的是利用数值方法研究狭窄对胆汁流动动力学的影响。我们采用了狭窄肝管内胆汁流动的数值计算流体动力学模型。我们研究并比较了狭窄严重程度、狭窄长度、偏心率和胆汁流动特性对胆汁流动动力学的影响。详细提供了胆汁流速、压力分布、压降和壁剪切应力。狭窄改变了正常的胆汁流动模式并增加了流动阻力。在狭窄的上游和下游位置，胆汁流速减慢。在狭窄喉部区域，胆汁流动加速，并在狭窄后面形成再循环。胆道系统的最大压降随着狭窄长度的增加而增加。偏心使气流偏离管道的中心线。偏转流的行为在狭窄下游显着改变。胆汁流动行为如减速和再循环可能导致胆汁淤积。狭窄会改变胆道中的胆汁流动，导致胆道流体动力学指标发生变化，这可能是胆结石形成和其他相关疾病的预兆。考虑胆管狭窄可能会导致更好的患者分层。