The velocity distribution of the liquid sheet formed by two low-speed impinging jets

In this study, the local velocities of the liquid sheet formed by two low-speed impinging jets were directly measured using a LDV (laser Doppler velocimetry) instrument. The spatial distribution of the local sheet velocities at the forward part of the sheet and the effects of the impingement angle and jet velocity on the sheet velocities were examined. A parabolic velocity profile across the pre-impinging jet greatly affected the sheet velocity distribution, causing the sheet velocities to decrease while the azimuthal angle increased. This was attributed to the movement of a high velocity core, existing in the pre-impinging jets, to the region around the axis of the sheet. In the radial direction, the local sheet velocities were a little low around the impinging point, and remained constant, but then decreased near the edge of the sheet. The dependence of sheet velocities on the impingement angle was confirmed, and the tendency towards an even distribution of sheet velocities was found to increase as the impingement angle increased. With the exception of the lowest velocities measured near the edge of the sheet, the local sheet velocities at the forward part of the sheet were higher than the mean jet velocity. (C) 2002 American Institute of Physics.