Experimental Study on Hydrothermal Plume Dynamics in a Stratified Salt Water Tank

Abstract:

Hydrothermal plumes are generated by high temperature hydrothermal venting systems occurred at many places along the mid-ocean ridges. The understanding of interaction between plumes and surrounding seawater are important since plumes transport significant heat and chemicals from the lithosphere to the ocean. This paper presents an experimental study on plume generation, mixing, entrainment and rising in a stratified salt water tank. The two-tank method is first improved to produce a stable linear stratification in the tank. A series of plume experiments using different orifice diameters and fluxes are then carried out to evaluate the characteristics of plumes. The stratification of salt water is measured and buoyancy frequency is calculated to provide the background information. The plume shape, flow field, rise height, and buoyancy flux are analyzed using image processing methods. The results show that the established experimental system is capable of providing stable linear stratifications for laboratory studies of hydrothermal plumes. The measured plume shapes and rise heights are in good agreement with available empirical formulae in the literature.