| 摘要 |
PURPOSE:To detect stably a vortex over a wide flow velocity range, by constituting a primary vibrating system of a platelike member displaced by pressure of the vortex, lowering its primary natural vibration, and making it coincide with the minimum frequency of the vortex. CONSTITUTION:When a vortex 22 is generated in an opening 42 side of a vortex generating body 2, a pressure difference is generated between an opening 41 and 42, a pressure difference is generated between a chamber 171 and 172 communicating with said openings, respectively, and a diaphragm 6 is rotated clockwise. Subsequently, when a vortex is generated in the opposite side of the vortex generator 2, the diaphragm 6 is rotated counterclockwise, and the diaphragm 6 executes vibration of one reciprocating motion against generation of a pair of vortexes. The natural vibration number is made to nearly coincide with the lowest frequency of the vortex by setting suitably a moment of inertia of the diaphragm 6 and a torsion spring constant of span bands 71, 72. Exciting force proportional to a square of frequency of the vortex is applied to a vibrator 5, and amplitude of the diaphragm 6 of the vibrator 5 becomes almost constant. Accordingly, the vortex is detected stably over a wide flow velocity range. |
