Donovan F M, Taylor B C, Su M C
Mechanical Engineering Department, University of South Alabama, Mobile 36688.
J Biomech Eng. 1991 Nov;113(4):476-84. doi: 10.1115/1.2895429.
The dynamic characteristics of catheter-transducer systems using rigid tubes with compliance lumped in the transducer and oscillatory flow of fluid in rigid tubes were analyzed. A digital computer model based on one dimensional laminar oscillatory flow was developed and verified by exact solution of the Navier-Stokes Equation. Experimental results indicated that the damping ratio and resistance is much higher at higher frequencies of oscillation than predicted by the one dimensional model. An empirical correction factor was developed and incorporated into the computer model to correct the model to the experimental data. Amplitude of oscillation was found to have no effect on damping ratio so it was concluded that the increased damping ratio and resistance at higher frequencies was not due to turbulence but to two dimensional flow effects. Graphs and equations were developed to calculate damping ratio and undamped natural frequency of a catheter-transducer system from system parameters. Graphs and equations were also developed to calculate resistance and inertance for oscillatory flow in rigid tubes from system parameters and frequency of oscillation.
分析了使用刚性管的导管 - 换能器系统的动态特性，其中顺应性集中在换能器中，且刚性管中有流体的振荡流动。基于一维层流振荡流开发了一个数字计算机模型，并通过纳维 - 斯托克斯方程的精确解进行了验证。实验结果表明，在较高振荡频率下，阻尼比和阻力比一维模型预测的要高得多。开发了一个经验校正因子并将其纳入计算机模型，以将模型校正为与实验数据相符。发现振荡幅度对阻尼比没有影响，因此得出结论，较高频率下增加的阻尼比和阻力不是由于湍流，而是由于二维流动效应。开发了图表和方程，以便根据系统参数计算导管 - 换能器系统的阻尼比和无阻尼固有频率。还开发了图表和方程，以便根据系统参数和振荡频率计算刚性管中振荡流的阻力和惯性。
