Intrusive gravity currents

This thesis will discuss equilibrium and non-equilibrium intrusive gravity currents or intrusions, in two layer and continuous stratifications. Although the associated time and length scales are significantly smaller than those appropriate to most natural flows of interest, insights can occur when discussing actual laboratory experiments provided that the Reynolds number is sufficiently large so that viscous effects do not show a leading order influence. Lock release experiments were performed and the speed was analyzed using DigImage and Digiflow. The equilibrium intrusion is discussed which is an extension of the doubly symmetric case, where the density of the current is the depth-weighted mean density of the layers. The non-equilibrium case is also discussed and unlike the equilibrium flow, the intrusion fluid steadily rises or falls behind the intrusion front, adding an additional source of energy to drive the flow. These intrusions were performed in two-layer and continuous stratifications. The results presented in this thesis include experimental and numerical data and follow closely to the work of previous researchers' theoretical models.