Experimental investigation of the effect of jet inclination on bifurcation of laminar jets

摘要

Submerged buoyant jets show interesting phenomenon like bifurcation under specific flow conditions. A detailed quantitative experimental analysis of this hydrodynamic instability highlighting relative importance of associated parameters is addressed in this work. Regular water and brine solutions have been used as the experimental fluids and flow diagnosis has been performed using Particle Image Velocimetry and shadowgraphy. It is found that for certain ranges of Reynolds number and Grashof number, the incoming jet cannot flow as a single entity, but rather bifurcates into a main jet whose motion is governed by the initial momentum of the jet and a buoyancy dominated thin sheet. The effect of incoming flow rate, angle and velocity of injection, and the density difference between the fluids on bifurcation are explicitly studied. The regions of bifurcation have been mapped on the Re-Gr~(1/2) plane for different orientations of both positive and negatively buoyant jet. The flow field reveals several interesting features like flow entrainment into the jet, jet bifurcation, bifurcation zone, transition zone and finally the turbulence of the jet.