Model experiments in vitro and numerical simulation on the interaction between pulsatile blood flow and elastic blood vessel

点击翻译按钮获取中文摘要

(1). The buckling and large deformation of collapsible tubes with very thin wall thickness as a model of blood vessel with high compliance was investigated both by experiments and numerical simulation. A changing contour of the cross section of the tube collapsing with the decrese in the transmural pressure was visualized by laser light sheet, and the cross sectional area was obtained from the internal area surrounded by the contour. The shape of the contour thus measured agreed well with that calculated using two-dimensional and three-dimensional theoretical models. Thus the tube law, i.e. the relationship between the cross sectional area of the tube and the transmural pressure was obtained both from the above-mentioned theories and experiment together with a conventional method of measuring the displaced tube volume due to collapse. Comparison between them revealed that the results from the three-dimensional theory agreed well with that from the experiments in the overall region of t … More he tube while the two-dimensional theory did so in the unaffected region by rigid connections at both ends of the tube. Pressure distribution along the tube axis in steady flow through the collapsed tube were able to be predicted fairly by the two-dimensional flow theory.(2). A high concentration suspension of soft and elastic spherical particles of alginic acid gel having diameter of about 10 mu m in water and physiological salt solution was developed as a model blood. This model blood obeyed the Casson's diagram of tau versus d gamma /dt which had the same apparent viscosity and a similar yield stress as the real human blood. Furthermore, from the experiments using a rheoscope with a high spped video camera, in the region of low shear rate less than about 100/sec, an abnormally high shear stress was shown which was caused by an aggregate of the gel particles, which is a very similar phenomenon as real blood cell forms a rouleaux when the shear rate is lower than about 100/sec.(3). The above-mentioned model blood was perfused through both a flexible tube and a rigid one to compare its flow characteristics with that of water. As a result, a clear difference between them was shown as follows ; velocity profiles across the both tubes in the flow of the model blood had more round shape compared with those in water flow regardless of laminar or turbulent flow. Hence, it can be used as a powerful substitute of real blood invarious experiments in vitro to simulate real blood flow. Less