| 摘要 |
PURPOSE:To measure a flow rate with high accuracy over a wide range by sectioning rectangularly a tube body where fluid flows, providing an obstacle which has a rectangular surface in the tube body, and generating a stable vortex street. CONSTITUTION:The tube body 11 is sectioned rectangularly, the obstacle 16 which has the rectangular surface for reducing the fluid in area to both right and left sides is arranged in the tube body, and an exciter 19 is fitted through an arm 20. Area reduction parts 18L and 18R formed on both right and left sides of the obstacle 16 are made rectangular having constant width (d) without reference to their positions and the obstacle 16 is vibrated by the exciter 19 as shown by an arrow 10 to vary the width (d) of the area reduction part 18L and 18R finely. Consequently, the condition of vortex street generation is the same at the center part and upper and lower end parts of the obstacle 1 and the stable vortex street is generated at its downstream side. Further, the vibration of the obstacle 16 is controlled automatically by using the output of a vortex detector 17 to make the vibration frequency resonate with the generation frequency of the vortex street, thereby generating the large vortex street.
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