Flow behaviour of negatively buoyant jets in immiscible ambient fluid

== Abstract ==

In this paper we investigate experimentally the injection of a negatively buoyant jet into a homogenous immiscible ambient fluid. Experiments are carried out by injecting a jet of dyed fresh water through a nozzle in the base of a cylindrical tank containing rapeseed oil. The fountain inlet flow rate and nozzle diameter were varied to cover a wide range of Richardson <math>Ri (8 x 10{−4} < Ri < 1.98)</math>, Reynolds <math>Re (467 < Re < 5,928)</math> and Weber <math>We (2.40 < We < 308.56)</math> numbers. Based on the <math>Re, Ri</math> and <math>We</math> values for the experiments, we have determined a regime map to define how these values may control the occurrence of the observed flow types. Whereas <math>Ri</math> plays a stronger role when determining the maximum penetration height, the effect of the Reynolds number is stronger predicting the flow behaviour for a specific nozzle diameter and injection velocity.