Characteristics of unsteadiness for transitional plane fountains in linearly stratified fluids

When a fountain is injected into a linearly stratified fluid, its behavior will be governed by the stratification of the ambient fluid, represented by the dimensionless temperature stratification parameter (s), in addition to the Reynolds number (Re) and the Froude number (Fr). In this study, a series of three-dimensional direct numerical simulations (DNS) were carried out using ANSYS Fluent for transitional plane fountains in linearly-stratified fluids with Re, F r and s over the ranges 28 ≤ Re ≤ 300, 3 ≤ F r ≤ 10, and 0.1 ≤ s ≤ 0.5 to study the effects of these governing parameters on the characteristics of such unsteadiness. Empirical correlations to quantify the effects of F r, Re and s over the studied ranges on the characteristics of the unsteadiness are also obtained and compared to the relevant scaling relations developed for weak plane fountains. Keywords: Direct numerical simulation, Plane fountain, Stratification, Transitional flow, Unsteadiness.