Laboratory simulations of atmospheric dynamics in the rotating fluid annulus experiments.

近十年来，人们逐渐认识到，研究流体中的拉格朗日运动在流体动力学、气象和海洋学问题中具有根本性的重要性。然而，到目前为止，只有少数这样的实验研究完成了。在本项目中，我们开发了在旋转流体环中观测三维拉格朗日轨迹的实验方法，该流体环被设计用于产生地球中纬度大气大尺度环流中的斜压波。中性浮力示踪粒子由荧光物质制成，在暗室中用紫外光照射，通过两台摄像机探测它们的位置。在那里，我们早期研制的双旋转转台装置被用来跟踪示踪粒子。在这个项目的第一年（1995年），我们开发了一种方法来制造长期浮力的示踪粒子。因此，我们成功地获得了总时间超过10小时的粒子轨迹数据。该结果已在日本物理学会、日本气象学会、日本流体力学学会和可视化学会上发表。描述这些实验的论文将很快发表。我们在实验中发现了波数4和波数5之间拉格朗日运动的显著差异。这在气象研究中是非常重要的，因为它表明不同波数的热输运机制是不同的。虽然我们的部分实验结果与Sugata和Yoden的数值模拟结果是一致的，但是我们的数据不足以得出可靠的结论。我们意识到在一次实验中进行10多个小时跟踪的必要性。在该项目的第二年（1996年），我们开发了一个用个人电脑自动跟踪示踪粒子的系统，以便于进行长期跟踪（超过10小时）。此外，我们还与三泰德比公司合作制作了紫外发光染料微胶囊作为示踪剂，并进行了实验测试，证明其非常适合作为示踪剂。我们计划在重新调查物理条件后进行未来的实验。少

In the recent ten years it has become gradualy acknowledged to be fundamentarlly importent in fluid dynamics, meteorological and oceanographical problems to investigate Lagrangian motions in fluids. Only a few such experimental studies, however, have veen so far done. In this project we have developed experimental method to observe 3-D Lagrangian trajectories in the rotating fluid annulus which is designed to produce baroclinic waves found in the large scale circulation of the atmosphere in the mid-latitud of the earth. Neutrally buoyant tracer particles are made from fluorescent matter and illuminated by ultraviolet light in the dark room to detect their position by two videocameras. There our early developed apparatus of double rotating turn-tables was used to track a tracer particle. In the first year (1995) of this project we developed the method to make tracer particles that are buoyant for a long time. Thus, we succeeded in obtaining the data of the particle trajectories for the … More total time of more than ten hours. The result has been reported at Physical Society of Japan, Meteorological Society of Japan, Fluid Dynamics Society of Japan and Visualization Society. The paper which describes these experiments will be soon published. New discovery in our experiments is a significant difference of the Lagrangian motions between the wavenumber-4 and 5 wave. This is very important in the meteorological studies because it suggest that the mechanism of the heat transport is different between the wavenumbers. Though a part of our experimental result is consistent with the result of the numerical simulation done by Sugata and Yoden, our data were insufficient for getting the reliable conclution. We realized neccesity of performing more than 10 hours tracking in one experiment. In the second year (1996) of this project we developed a system of tracking a tracer particle automatically with a personal comuter in order to make it very easy to perform long term trackings (for more than 10 hours). Furthermore we made microcapsuls of ultraviolet luminous dye as tracer particles with the cooporation of Threetech Debys Co. and tested them in experiments so that they were proved to be very suitable for tracers. We have a plan to carry out future experiments after reinvestigating the physical conditions. Less