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目的 探讨狭窄管流中一系列流动指标的定量检测方法 ,包括 Reynolds数、相对频带展宽度(RSB)、层流剪应力、法向雷诺应力 (RNS)等。方法 采用临床使用的脉冲多普勒血流仪在狭窄前后多个位点进行多时点检测 ,得出流场特征 ,再分别评价各项指标。结果 定性评价见狭窄下游呈现鲜亮的“烛焰形”花色镶嵌湍流流型 ,狭窄后 1.0 cm处得到较大的 RSB、RNS等 ,1/ 2 R取样容积处湍流指标大于相应的轴心处。结论 狭窄后1.0 cm1/ 2 R取样容积处存在最大的湍流度 ;狭窄后各位点的数据离散度大于狭窄前。该研究为进一步在不同流场中开展生物力学的在体研究奠定了前期工作基础
Objective To explore a series of quantitative detection methods of flow index in narrow tube flow, including Reynolds number, relative band width (RSB), laminar shear stress and normal Reynolds stress (RNS). Methods Pulsed Doppler flowmeter was used to detect multi-time points at various sites before and after stenosis, and the characteristics of the flow field were obtained. Then the indexes were evaluated respectively. Results The results of qualitative evaluation showed that there was a bright “candle-flame” mosaic inlaid turbulent flow pattern downstream of the stenosis, and RSB, RNS and others were larger at 1.0 cm after stenosis. The turbulence index at the 1/2 R sampling volume was larger than that at the corresponding axial center. Conclusion The maximal turbulence exists at the 1.0 cm1 / 2 R sampling volume after stenosis, and the data dispersion degree of each site after stenosis is greater than that before stenosis. The study laid the foundation for further studies on in-vivo biomechanics in different flow fields