Affiliations: Kanagawa Institute of Technology, 1030 Shimo-ogino,
Atsugi-shi, Kanagawa 243-0292, Japan | Kogakuin University, 2665-1 Nakano-cho, Hachioji-shi,
Tokyo 192-0015, Japan
Abstract: In order to clarify the metering characteristics of the fluidic
flowmeters employing self-sustained oscillation, the oscillating jets in a
feedback oscillator and a target oscillator were visualized and the
differential pressures across the jets were measured. The experiment clarified
that the fluidic oscillators could be classified into three types, i.e.,
feedback type, reflection type and recirculation type oscillators. The jet
oscillation was caused by external feedback control pressures in the feedback
type oscillator. On the other hand, the internal feedback pressure difference,
produced mainly by a partly reflected jet flow from the target, sustains the
jet's oscillation in the reflection type oscillator. In the recirculation type
oscillator, the jet oscillation was caused by the internal feedback pressure
difference produced by a jet flow recirculating along the side wall of the
target oscillator under the influence of the reflected jet flow. The jet
oscillation of the target oscillator was influenced by forced pulsation of the
jet flow as follows. The strength of the reversed jet flow and reflected jet
flow was affected directly with the pulsation of the jet and a synchronization
phenomenon appeared, in which the oscillation frequency was matched with the
pulsation frequency of the jet flow. The ranges of dimensional parameters
maintaining the oscillation of the target oscillator were revealed. It was
found that the target oscillator with crescent target could produce steady
oscillation in a wider region of dimensional parameters.
