The effects of major flow path geometries on the flow characteristics of a Fluidic Device (FD) have been investigated experimentally and numerically. A full-scale FD has been designed and tested to verify the required characteristics, and the geometric effects are examined by changing the internal shape of the FD. As characteristics of the FD, time dependent flow rate, flow turndown and water level change are discussed. The flow turndown ratios are in the range of about 2 to 4, and they are highly depend on the exit nozzle diameter and the control port width, but almost not affected by the chamber height. As the flow turndown ratio increases, the water level in the pipe connected to the supply port becomes unstable, and it limits the flow turndown ratio, which is 2.5 in our case. The numerically predicted flow conditions in FD were highly dependent on the turbulence models, among them the RSM model gave the most reasonable results. In a high swirl case, the difference of flow rate between the test and the numerical simulation was about 10%. As the size of exit nozzle decreases, reverse flow in the cavity of the core increases and consequently the discharge flow rate reduces. In a low swirl case, the flow field in the chamber is extremely complicated and shows transient characteristic where the flow pattern in the core shows a large-scale oscillation.

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