FORWARD AND BACKWARD RUNNING WAVES IN THE ARTERIES - ANALYSIS USING THE METHOD OF CHARACTERISTICS
FORWARD AND BACKWARD RUNNING WAVES IN THE ARTERIES - ANALYSIS USING THE METHOD OF CHARACTERISTICS
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DOI：
10.1115/1.2891191
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发表时间：
1990-08-01
影响因子：
1.7
通讯作者：
JONES, CJH
中科院分区：
文献类型：
--
作者：
PARKER, KH;JONES, CJH
弹性动脉中的一维流动方程是双曲的，并且允许平均速度U和压力p的非线性波状解，忽略耗散，解可以用小波来表示，小波定义为特征之间的黎曼不变量的差异。这一分析表明，dUdP对于正向运行的小波是正定的，对于反向运行的小波是负定的，从而可以根据在动脉中某一点测量的压力和速度来确定小波的净量级和传播方向。利用相交小波是相加的线性化假设，可以分别计算正向和反向运行的小波。该分析应用于人类升主动脉的测量，表明在主动脉血流的加速和减速阶段，前向运行小波都占主导地位。使用线性化分析计算的正反行波与数据阻抗分析的结果相似。然而，与阻抗分析不同的是，这是一种时域分析，可以应用于非周期或瞬态流动。
The one-dimensional equations of flow in the elastic arteries are hyperbolic and admit nonlinear, wavelike solutions for the mean velocity, U, and the pressure, P. Neglecting dissipation, the solutions can be written in terms of wavelets defined as differences of the Reimann invariants across characteristics. This analysis shows that the product, dUdP, is positive definite for forward running wavelets and negative definite for backward running wavelets allowing the determination of the net magnitude and direction of propagating wavelets from pressure and velocity measured at a point in the artery. With the linearizing assumption that intersecting wavelets are additive, the forward and backward running wavelets can be separately calculated. This analysis, applied to measurements made in the ascending aorta of man, shows that forward running wavelets dominate during both the acceleration and deceleration phases of blood flow in the aorta. The forward and backward running waves calculated using the linearized analysis are similar to the results of an impedance analysis of the data. Unlike the impedance analysis, however, this is a time domain analysis which can be applied to nonperiodic or transient flow.