Experimental investigation of wastewater discharges from a Rosette-type riser using PIV

The under-pressure-induced-ambient flow velocity and the bending phenomenon of the horizontal buoyant jets on a Rosette-type riser with four ports were observed by conducting the hydraulic experiments over a certain range considering the initial moment um and initial buoyancy. The measurement accuracy associated with the PIV system was verified. The velocity of the ambient flows into the inner side of the surrounding buoyant jets increased initially, and then decreased with the increase of the densimetric Froude number. The trajectories for low densimetric Froude numbers tended to rise up without strong bending whereas high densimetric Froude numbers resulted in more strongly bending trajectory and then led to the release of the bending trajectory with the increase of the densimetric Froude number. The low bending height resulted from the strongly bending buoyant jet. The experimental results revealed that the trajectories bend to the inner side with the increase of the ambient flow velocity.