On the coalescence of colliding jets

The paper investigates the transition from non-coalescence to coalescence of two immersed colliding jets. Solutions of water and glycerol were injected in mineral oil through two symmetric needles using a syringe pump. At low Reynolds numbers the two jets are in a stable non-coalescence state. The jets coalescence at a certain Reynolds and Webber number, determined by experiments. The critical dimensionless numbers, that quantitatively capture the transition, are calculated. In the experiments, viscosity was increased by modifying the concentration of glycerol in the solution to emphasize its influence over the transition from non-coalescence to coalescence.