DID YOU KNOW? DTIC has over 3.5 million final reports on DoD funded research, development, test, and evaluation activities available to our registered users. Click HERE
to register or log in.
Double-diffusive Intrusions: Dynamics and Transport
Intrusions are found throughout the ocean and are suspected to significantly transport salt, heat, nutrients, and pollutants laterally in ways that can have large impacts on large-scale ocean circulation. We perform the first fully resolved simulations that allow for the natural development of intrusions at an arbitrary inclination. This allows us to characterize their small-scale mixing and their lateral transport. We use these results to develop a less computationally expensive model that parameterizes the small-scale mixing of microscale double-diffusive processes in a multi-dimensional simulation. Such studies have been limited to one-dimensional simulations in the past. We test this parameterized model by comparing the results to a comparable fully resolved simulation. This allows us to perform simulations on more physically relevant scales for intrusions, which will allow us to explore the dependencies of heat and salt transport on our governing parameters of density ratio, aspect ratio, and isothermal slope. We find that intrusion-driven transport decreases with increasing density ratio and that the results depend strongly on the aspect ratio of the domain. Both fully resolved simulations and some parameterized simulations are dominated by collective instabilities. However, other parameterized simulations, particularly those at low density ratios, show the development of direct mode intrusions, and they evolve into thermohaline staircases.
Approved For Public Release