Abstract
The experimental study has been conducted to investigate the characteristics of the turbulent jet within the liquid fluid amplifier. Dimensions of the fluidic element used are proposed to be aspect ratio: 1.9, main nozzle width b: 10.0mm, offset D: (0∼3.0) b (variable) and side wall angle α: 0°∼30° (variable). The operating liquid is water of about 20°C.
In order to analyze the jet behavior the flow patterns of the attached jet are visualized in an arbitrary horizontal section by means of air bubble tracer and slitted ray of about 0.5mm thickness, and static pressure distributions are measured in various jet velocities, side wall angle and offsets.
The following results of the experimental study are obtained: (1) The attachment stream line and the attachment point are the same in any horizontal section. The attachment point can be defined as the point on which the velocity component parallel to a side wall is zero. (2) The static pressure distributions of vortex on the attached side are obtained. The isobaric curves are almost circular and their distributions are squarely proportional to the radial distance from the vortex center in the inner region of the vortex. From the fact that the jet partly flows into the forced vortex, it is felt that the momentum theory may not be strictly applicable to the attached jet flow. (3) In the turbulent region the attachment length decreases and the vortex center also moves to the upper stream in accordance with the increase of Reynolds number. Both the attachment point and the vortex center gradually approach to constant positions in high Reynolds number. It is remarkable that the position of the vortex relative to the attachment point or to the attachment stream line is independent of the Reynolds number.
