Plane Offset Jet Discharged into Water of Finite Depth

Abstract

A plane submerged turbulent water jet discharged parallel to the offset bottom wall in a channel with a finite water depth was investigated experimentally. Depending on the depth of the nozzle and its height from the bottom, the jet deflects towards either of two boundaries, the free surface or the solid wall. Detailed data on the velocity field measured by the Particle Image Velocimetry (PIV) method are obtained to examine the effect of the opposite boundary on the deflecting jet and the difference in the jet development between the deflection to the free boundary and that to the solid boundary. The mean velocity profiles and the spread rates of the jet are compared with those of a conventional plane free jet by applying a curved coordinate system along the jet centerline.

Deflection of jets discharged into a reservoir with a free surface

“…Similar diagrams with figures 12(a) and (b) were obtained in experiments by Sudo et al (1998), Shimada et al (2004) and Tsunoda et al (2006) although their experiments were performed at much larger Reynolds numbers such as Re = 4430-177 00 (Sudo et al 1998, Shimada et al 2004 and Re = 2500 (Tsunoda et al 2006) and the length of the channel (L in figure 1) was much longer. They concluded that the direction of deflection of the flow is determined solely by the values of h 1 and h 2 , independently of the Reynolds number, and they attributed the mechanism of deflection to the Coanda effect.…”

“…Multiple stable states of flow through the reservoir with a free surface were found in experiments by Shimada et al (2004) and confirmed by Tsunoda et al (2006), which was unexpected because the flow was thought to be determined uniquely for such an asymmetric configuration. We traced the origin of the multiple flows up to the pitchfork bifurcation of flow in a symmetric channel with two rigid boundaries by using polymorphic transformations.…”

“…It has been long thought that the deflection of jets issuing at a middle height is uniquely determined by the configuration of the reservoir. However, Sudo et al (1998) and Shimada et al (2004) found in their experiments that a planar submerged water jet discharged into a reservoir with a free surface deflects towards either of the two boundaries, which was confirmed by Tsunoda et al (2006). The two kinds of deflected flow are realized in a range of the depth and the height of the inlet throat or nozzle, while the flow always deflects either to the free surface or to the bottom in the two extreme conditions where the throat is close to the free surface or to the bottom, respectively.…”

Numerical Investigation of Nozzle Geometry Effect on Turbulent 3-D Water Offset Jet Flows

“…An offset jet with small offset ratio has also been studied previously by Lund (1986). The flow field of a plane offset jet that discharges between a free surface and a solid wall was investigated experimentally by Tsunoda et al (2006). Miozzi et al (2010) also worked on a plane offset jet that discharges in the free surface surrounding fluid.…”