Study on Development of Measurement System and Dynamic Image Display for Flow Pattern in Hydrautic Experimental Flume

最近高科技仪器的进步使水文实验中的测量变得相对便宜。然而，与数值模拟的进展相比，水文试验很难给出结果。本文针对由咸水层和淡水层组成的密度流，将摄像机记录的实验渠内水文现象与数值模拟结果进行了对比，虽然用染料可视化记录了密度流，但在现阶段很难将其完美地转化为流速矢量。在密度流模拟方面，已建立了初步的算法，但目前的超级计算机需要数天时间才能进行一系列计算，计算机性能必然需要进一步提高(并行连接4台超级计算机可使处理速度提高一倍或三倍)，然后将该技术应用于小岛淡水湖，扩大规模，将浅水波动方程发展为平面二阶方程。根据可能与卫星图像的比较，上述方法可望成为在大范围内进行环境测量和分析的有效工具。通过同时采用地理信息系统技术，我们希望这些方法在实际应用中对环境分析有用。今年，我有机会在英国邓迪大学见证了类似的实验。他们利用激光和光素完成了可视化。这段经历非常有启发性。

Recent advancement in high technology instruments has enabled measurements in the hydrological experiments relatively cheaply. However, in comparison to the progress in numerical simulations, hydrological experiments are difficult to give results for the troubles taken. Here, focusing to the density flow consisting of two salt and fresh-water layers, the hydrological phenomena in the experimental canal recorded by a video-camera are compared with the results of numerical simulation.Although the density flow was recorded by visualizing with dye, it is hardly said at the present stage that the flow is perfectly converted to flow velocity vectors. In relation to density flow simulation, algorism in the initial stage has been established but several days were taken for a series calculation by the present super personal computer and a need for further improvement of computer performance is inevitable (processing speed shall be doubled or tripled by connecting 4 super computers in parallel).Then, the technique was applied to the fresh water lake of Kojima by enlarging the scale and developing the shallow-water wave equation into the plane secondary-order equation. The above methods are expected to serve as effective tools for environmental measurements and analysis in wide areas based on possible comparison with satellite images. By simultaneous adoption of GIS techniques, we expect these methods to be useful for environmental analyses in practical applications.This year, I had an opportunity to witness similar experiments at Dundee University, United Kingdom.They accomplished visualization using laser light and photogens. This experience was very instructive.