A numerical model of mixing and convection driven by surface buoyancy flux
MetadataShow full item record
This thesis studies mixing and convection in a rectangular basin driven by a specified heat flux at the surface. A numerical model is constructed for this purpose. The main focus of the study is on the density and circulation structure resulting from the thermal forcing. In chapter two, a simple vertical one-dimensional model is developed to examine the mixing processes under a given surface heat flux. In order to simulate strong vertical mixing in the region where stratification is unstable, turbulent processes are modeled by a convective overturning parameterization of eddy viscosity and diffusivity. The results show that the density structure is strongly affected by the convective overturning adjustment as surface cooling prevails, and the resulting density field is nearly depth independent. In chapter three, a more complicated two-dimensional model is constructed to simulate mixing and circulation in a vertical rectangular basin with rigid boundaries. The aspect ratio of the basin ranges from 1 to 0.001 and Rayleigh number from 104 to 2 x 1012. It is found that the circulation pattern is dominated by these two important numbers. The roles of density overturning and density-momentum overturning mixing are further investigated. The results show that the convective overturning not only homogenizes the density field in the unstably stratified region but also contributes to increase the circulation. A crude scale analysis of the system shows that the characteristics of the density and momentum fields from the analysis agree well with the numerical results.
Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1989
Suggested CitationThesis: Wang, Xiaoming, "A numerical model of mixing and convection driven by surface buoyancy flux", 1989-09, DOI:10.1575/1912/5387, https://hdl.handle.net/1912/5387
Showing items related by title, author, creator and subject.
Moffat Varas, Carlos F. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2007-09)Observations of current velocity, temperature, salinity and pressure from a 2-year moored array deployment and four hydrographic cruises conducted by the United States Southern Ocean GLOBEC program on the western Antarctic ...
French, Katherine L. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2015-02)Tracing the evolution of Earth’s redox history is one of the great challenges of geobiology and geochemistry. The accumulation of photosynthetically derived oxygen transformed the redox state of Earth’s surface environments, ...
Sugimura, Peter Joseph (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2008-09)The mid-to-deep Arctic Ocean is generally characterized by a cyclonic circulation, contained along shelves and ridges. Here we analyze the general Arctic circulation using an idealized numerical model consisting of a ...