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Abstract
Hydrothermal vents have a large and multidisciplinary impact on the ocean, and represent a rich and diverse field of study. In this research, we focus first on the physical characteristics of an individual plume and second on the influences of hydrothermal venting on fluid circulation patterns over a ridge valley system.
To study the turbulent and internal characteristics of a single focused hydrothermal vent plume, a large eddy simulation (LES) turbulent convection model for a hydrothermal fluid injected into a tidally modulated stratified crossflow is used. The goal is to characterize the fine scale dissipation rates of turbulent kinetic energy (TKE) and thermal variance. In characterizing the turbulent quantities we make several interesting discoveries: the use of isotropic Smagorinsky mixing coefficients is invalid in focused venting, the dominant components of TKE dissipation and thermal variance dissipation are shear production and advection respectively, advection of thermal variance is an important factor to take into consideration, and the main contributing factor of the refractive index observed by acoustic scintillation is the thermal variance dissipation.
To study the regional effects of multiple venting fields on flow circulation within a ridge valley and to characterize the magnitude and patterns of flow brought about by combined diffuse and focused venting, we utilize the finite-volume community ocean model (FVCOM) to build a high resolution simulation of the Endeavour Ridge segment. Results show the cumulative effects of multiple hydrothermal vent fields, vent induced vertical motion, and strong topographical forcing throughout the region. Our results support the presence of hydrothermal circulation cells most clearly seen where crossflow is weakest. The scale of these cells is on the order of several hundreds of meters in diameter.
To study the turbulent and internal characteristics of a single focused hydrothermal vent plume, a large eddy simulation (LES) turbulent convection model for a hydrothermal fluid injected into a tidally modulated stratified crossflow is used. The goal is to characterize the fine scale dissipation rates of turbulent kinetic energy (TKE) and thermal variance. In characterizing the turbulent quantities we make several interesting discoveries: the use of isotropic Smagorinsky mixing coefficients is invalid in focused venting, the dominant components of TKE dissipation and thermal variance dissipation are shear production and advection respectively, advection of thermal variance is an important factor to take into consideration, and the main contributing factor of the refractive index observed by acoustic scintillation is the thermal variance dissipation.
To study the regional effects of multiple venting fields on flow circulation within a ridge valley and to characterize the magnitude and patterns of flow brought about by combined diffuse and focused venting, we utilize the finite-volume community ocean model (FVCOM) to build a high resolution simulation of the Endeavour Ridge segment. Results show the cumulative effects of multiple hydrothermal vent fields, vent induced vertical motion, and strong topographical forcing throughout the region. Our results support the presence of hydrothermal circulation cells most clearly seen where crossflow is weakest. The scale of these cells is on the order of several hundreds of meters in diameter.