Developmental Research on Instrumentation of Hydraulic Experiments

本研究由7所大学的9名水力学实验负责人共同完成，目的是通过个人计算机控制来节省实验中的人力，实现测量和数据采集的自动化，并确保复杂实验条件的重现性。3年的研究结果可以总结如下.在实验管道中产生所需的流速通过逆变器将0-60 Hz范围内的可选频率的电流提供给电动机，从而给出相应的转数。与以往的流量设定方法相比，该系统可以通过更简单的程序来产生目标流量，并且实现了显著的节能。通过电磁流量计或超声波流量计确认排放的准确性。此外，发现通常以30 -40 Hz频率驱动电机有助于节能。随着微机电压控制功能的加入，可以给出随时间变化的任意放电曲线，这为今后的非恒定流实验提供了很大的前景.通过闸门控制产生脉动流通过使用线性电机操作闸门，并使用电位计反馈闸门位置，可以获得所需的频率（5秒以上）和振幅（10 cin以下）/使用该装置，可以在运河内再现目标脉动流或浪涌现象。3.简化实验，节省大型水池的人力用伺服电机控制牵牛花型溢流堰的位置，并将水位计的测量值输入微机，可准确了解大型水池的水力状况。因此，以前由几个人组成的团队进行的实验已经变成了由1- 2个人从远程控制室进行的实验。

The present study was conducted by 9 researchers, who are in charge of hydraulic experiments at 7 universities, with the aim of saving man power in experiments, automation of measurement and data collection and ensuring reproducibility of complicated experimental conditions by personal computer control. The results of 3-year study can be summarized as follows.1. Generation of desired flow rate in an experimental canalAn electric current of optional frequency in the range of 0-60 Hz was supplied to a motor by an inverter giving a corresponding number of revolution. With this system, the aimed flow rate could be generated by simpler procedure and marked energy-saving was achieved in comparison to the previous method for flow rate set-up. Accuracy of discharge was confirmed by an electromagnetic flow meter or ultrasonic flow meter. Further, it was found that the motor was usually driven at 3O-40 Hz frequency contributing to energy-saving. With the addition of voltage control by a personal computer, it will become possible to give optional discharge curves which vary with time presenting a big prospect for experiments on unsteady flow in the future.2. Generation of fluctuating flow by gate controlDesired frequency(longer than 5 seconds)and amplitude(below 10 cin)became obtainable by operating a gate with a linear motor and, feeding back the gate position with a potentiometer/ With this device, it became possible to reproduce aimed fluctuating flows or surging phenomena within the canal.3. Simplification of experiments and man power saving in a large-scale water tankControl of the position of an overflow weir of morning glory type by a servo-motor and input of measurement values from water gauge to a personal computer enabled accurate comprehension of hydraulic conditions in a large-scale water tank. Thus, an experiment which was formerly conducted by a team of several people has became maneuverable by 1- 2 people from a remote control room.