Woo Y R, Yoganathan A P
Med Instrum. 1985 Sep-Oct;19(5):224-31.
The velocity and turbulent shear stress measured in the immediate vicinity of prosthetic heart valves play a vital role in the design and evaluation of these devices. In the past hot wire/film and one-component laser Doppler anemometer (LDA) systems were used extensively to obtain these measurements. Hot wire/film anemometers, however, have some serious disadvantages, including the inability to measure the direction of the flow, the disturbance of the flow field caused by the probe, and the need for frequent calibration. One-component LDA systems do not have these problems, but they cannot measure turbulent shear stresses directly. Since these measurements are essential and are not available in the open literature, a two-component LDA system for measuring velocity and turbulent shear stress fields under pulsatile flow conditions was assembled under an FDA contract. The experimental methods used to create an in vitro data base of velocity and turbulent shear stress fields in the immediate vicinity of prosthetic heart valves of various designs in current clinical use are also discussed.
在人工心脏瓣膜紧邻区域测量的速度和湍流剪应力在这些装置的设计和评估中起着至关重要的作用。过去，热线/热膜风速仪和单分量激光多普勒测速仪（LDA）系统被广泛用于获取这些测量数据。然而，热线/热膜风速仪存在一些严重缺点，包括无法测量流动方向、探头对流场的干扰以及需要频繁校准。单分量LDA系统不存在这些问题，但它们不能直接测量湍流剪应力。由于这些测量至关重要且公开文献中没有相关内容，根据美国食品药品监督管理局（FDA）的合同组装了一个用于在脉动流条件下测量速度和湍流剪应力场的双分量LDA系统。还讨论了用于创建当前临床使用的各种设计的人工心脏瓣膜紧邻区域速度和湍流剪应力场体外数据库的实验方法。
