Low Reynolds number fluidic flowmetering

Abstract

The capability of flowmeters to function at small Reynolds numbers (<200) is vital in many applications where low flows or high viscosities are encountered, such as the metering of oil, respiratory flows, domestic gas and point-of-sale metering. The principle of operation of one such fluidic flowmeter, the target meter, is explained by means of flow visualisations and dynamic pressure distribution analyses. The performance characteristics of the meter are reported in detail. Minimum Reynolds numbers as low as 54 are attained. Also it is shown that the difficult calibration zones encountered in conventional fluidic flowmeters during jet transition to turbulence can be eliminated.