Axis Switching of Free-Falling Elliptical Water Jets

Abstract

This study experimentally investigated the axis switching of free-falling water jets issued from an elliptical nozzle with an aspect ratio of 1.6. High-speed photography was used to capture the flow behaviors. The axis-switching wavelength of the elliptical jets was found growing with the falling distance while its amplitude was decaying. The variation of the jet cross-sectional area could be estimated based on free-falling velocity. An increasing axis-switching frequency with the falling distance was observed in the experiments and was estimated by introducing a correction factor for the gravity effect into Rayleigh’s equation. Finally, an estimation method for the axis switching of elliptical water jets was developed and the predictions compared well with the experimental measurements.