著者

横田,祥

出版者

日本流体力学会

雑誌

日本流体力学会年会講演論文集

巻号頁・発行日

vol.2010, 2010-09-09

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In the terrestrial and planetary atmospheres, vortices that exhibit a polygonal shape are occasionally observed even when the external conditions are nearly axisymmetric. Similar phenomena are also found in laboratory experiments in which water layer in a right cylindrical tank is driven by a rapidly-rotating bottom disk. In this study, we have studied these phenomena by means of laboratory experiments and a linear stability theory. It is found that the characteristics of the vortices in the laboratory experiments are well explained by those of the fastest growing waves caused by a horizontal shear instability of the basic flow. Thus, the polygons observed in the laboratory experiments are likely to be caused by a shear instability.