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 Ri (8×10 -4 < Ri < 1.98) , Reynolds Re (467 < Re < 5928) and Weber We (2.40 < We < 308.56) numbers. Based on the Re, Ri and We 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 Riplays 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.

On the modelling of steady turbulent fountains

“…(17). For convenience, approximate solutions are first drawn for this equation in the cases corresponding to forced (C i ( 1) fountains (see Appendix 2).…”

“…It is the reason why an extensive literature is devoted to that topic. The interested reader is referred to works by [14] and [17] for immiscible fountains, [22,33,35] for miscible laminar fountains, [18,38] for plane turbulent fountains and [1,2,6,8,9,16,25,34,37] for round turbulent fountains in both homogeneous and stratified ambients. Note that most of these studies have focused on the determination of fountain heights.…”

Numerical simulations of negatively buoyant jets in an immiscible fluid using the Particle Finite Element Method

“…Full details concerning the experimental apparatus, method, and the main results obtained are available in Geyer et al [26]. Full details concerning the experimental apparatus, method, and the main results obtained are available in Geyer et al [26].…”

“…Here, we go a step further and apply the scheme to investigate the dynamics of negatively buoyant jets in a homogenous immiscible ambient fluid. We compare the numerical predictions with experimental observations outcomes from a more detailed experimental study by Geyer et al [26]. The simulations include the effect of surface tension and the sharp jumps in the density and viscosity of the fluids at the interface.…”

“…We have performed 12 two-dimensional numerical simulations, which are compared with more than 70 experimental results of a parallel study by Geyer et al [26]. In the different numerical runs, we have varied the injection velocity and the nozzle radius to reproduce the wide range of Reynolds and Froude numbers covered by the experiments.…”