Characteristics of Sloshing Suppression by Active Control of Liquid Flow and its Suppression Mechanism

用亚克力板制成的600x500x50的矩形水箱，在水箱底部的每个角落都安装有喷嘴、电磁阀、塑料管和泵，安装在机械振动台上，用于激发水箱内300 mm的水的晃动。首先，我们发现从喷嘴喷出的间歇性水射流可以激发水的晃动振荡。然后对充水300mm的水箱进行正弦激励，使其在水中产生充分的晃动振荡，并研究了通过在每个喷嘴处喷射水射流来抑制晃动的特性，以明确晃动振荡的水射流喷射时间。我们发现水射流可以很好地抑制晃动。利用漂浮在水中的塑料微粒对射流喷射过程进行流动显示，充分抑制了晃动。对间歇式水射流抑制晃动的流型进行了图像分析，发现了一种非常奇特的两大反旋涡流型，这可能是间歇式水射流抑制晃动的主要机理。开发了用于分析水的晃动运动的有限元程序，并通过对比实验结果验证了程序的有效性，但发现用于分析正弦激励和间歇水射流作用下水流运动的有限元程序存在一个问题。

A rectangular tank of 600x 500x 50, made of acrylic plate, was equipped with a nozzle at each corner of bottom of the tank, electro-magnetic valves, plastic tube and pump and installed on the mechanical shaking table for exciting the sloshing of water filled in the tank up to 300 mm.First we found the intermittent water jet ejected from the nozzle can excite the sloshing oscillation of the water. Then the tank filled by water by 300 mm was sinusoidally excited for generating the full sloshing oscillation in the water and the characteristics of the suppression of the sloshing by ejecting the water jet at each nozzle were investigated for clarifying the water jet ejecting timing for the sloshing oscillation. We found that the water jet ejection can successfully suppress the sloshing. The flow visualization by using fine plastic particles floating in the water was conducted during the water jet ejection and the sloshing was fully suppressed. The image analysis of the flow pattern for the sloshing suppression by the intermittent water jet ejection revealed the very peculiar flow pattern showing two large vortices counterwisely circulating which may thought the major mechanisms to suppress the sloshing by the intermittent water jet ejection. FEM computer code was developed for analyzing te sloshing motion of the water and its validity was checked by comparing the experimental result but we found there is one problem in the FEM program for analyzing the water flow motion under the sinusoidal excitation and intermittent water jet ejection.