霧によって可視化された大気中のハイドロリック ジャンプ [in Japanese] Hydraulic jump in the atmosphere visualized by fog [in Japanese]
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This study deals with the mechanism of a local wind called "Hijikawa Arashi" which is a down slope wind observed along the Hijikawa river near Nagahama in Ehime Prefecture. This river is connected to an inland basin (Ohsu basin) where a cold air mass is accu nulated during nighttime by radiation cooling and overflows to the sea (Iyo-nada of Seto Inland Sea) through a valley along the Hijikawa river. Hijikawa Arashi gives a considerable influence to daily life of the people in the area, because the wind speed sometimes exceeds 10m/s and fog associated with the wind reduces the visibility significantly. The mechanism of the strong wind is not known yet, and remains as an interesting problem to meteorologists.<BR>In this study, Hijikawa Arashi is studied by means of a shallow water theory, laboratory experiment and field observation. It is shown that the strong wind is caused by a hydraulic jump of the down slope wind which is produced by the effect of topography of the valley. The theory and the laboratory experiments predict that a steady hydraulic jump is produced in the downstream side of the narrowest portion of the valley. The result was confirmed by a videotape record of the fog which visualized the hydraulic jump of the Hijikawa Arashi.
- Transactions of Visualization Society of Japan
Transactions of Visualization Society of Japan 18, 229-232, 1998-07-01
The Visualization Society of Japan