The air flow in the human bronchial tree is simulated in the normal and pathological cases. Analytical formulas are derived to design the full bronchial tree. All surfaces of the bronchial tree are matched with the second order of smoothness (there are no acute angles or ribs). The geometric characteristics of the human bronchial tree in the pathological case are modeled by a “starry” shape of the inner structure of the bronchus; the pathology degree is defined by two parameters: bronchus constriction level and degree of distortion of the cylindrical shape of the bronchus. A numerical technique is proposed for stage-by-stage computing of air motion in the human bronchial tree. A laminar air flow in the human bronchial tree is computed from the input bronchus to alveoli). It is demonstrated that the pressure decrease in the case of a laminar air flow in the bronchial tree is twice smaller than that in the turbulent case. Distortions of the cylindrical shape of the bronchi in the pathological case lead to a more significant pressure decrease in the bronchial tree.

中文翻译：

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人体支气管树三维模型——正常和病理情况下的气流建模

在正常和病理情况下模拟人体支气管树中的气流。推导出分析公式来设计完整的支气管树。支气管树的所有表面都与二级光滑度匹配（没有锐角或肋条）。病理情况下人体支气管树的几何特征以支气管内部结构的“星状”形状为模型；病理程度由两个参数定义：支气管收缩水平和支气管圆柱形状的扭曲程度。提出了一种数值技术，用于逐步计算人体支气管树中的空气运动。人体支气管树中的层流气流是从输入的支气管到肺泡计算的）。结果表明，支气管树中层流气流的压力下降比湍流情况小两倍。病理情况下支气管圆柱形状的扭曲导致支气管树中更显着的压力降低。