Semi-collapse of turbulent fountains in stratified media and the mechanisms to control their dynamics

Turbulent fountains are widespread natural phenomena with numerous industrial applications. Extensive research has focused on the temporal evolution and maximum height of these fountains, as well as their dependence on Reynolds and Froude numbers. However, the minimum height of the surrounding ambient fluid, which is removed by the fountain due to the entrainment effect, has received little attention. In this study, we investigate the dependence of this minimum height on the characteristics of the fountain and demonstrate how to control it. Our findings present important implications for technological applications of turbulent fountains, particularly in contaminant withdrawal. We discuss the potential of our results to improve the efficiency of such applications.