Ultraefficient reduced model for countercurrent two-layer flows

Ultraefficient reduced model for countercurrent two-layer flows

Nonlinear Stability of Two – Layer Flows ∗

We study the dynamics of two–layer, stratified shallow water flows. This is a model in which two scenarios for eventual mixing of stratified flows (shear-instability and internal breaking waves) are, in principle, possible. We find that unforced flows cannot reach the threshold of shearinstability, at least without breaking first. This is a fully nonlinear stability result for a model of strati...

Small Probability Events for Two-layer Geophysical Flows under Uncertainty

The stochastics two-layer quasi-geostrophic flowmodel is an intermediate system between the single-layer two dimensional barotropic flow model and the continuously stratified three dimensional baroclinic flow model. This model is widely used to investigate basic mechanisms in geophysical flows, such as baroclinic effects, the Gulf Stream and subtropical gyres. A large deviation principle for th...

Comparison between a non-hydrostatic numerical model and analytic theory for the two-layer exchange flows

Recently, Armi and Riemenschneider (2008) improved the two-layer hydraulic theory and applied it to the co-located sill and contraction. The main goal in this study is to compare the new theory with a non-hydrostatic numerical model. To this end, the numerical model is employed for two different geometries. The first geometry is steep topography with co-located contraction and the second geomet...

Predicting Extreme Events for Passive Scalar Turbulence in Two-layer Baroclinic Flows through Reduced-order Stochastic Models

The capability of using imperfect stochastic reduced-order models to capture crucial passive tracer statistics such as tracer energy spectrum, tracer intermittency, and eddy diffusivity is investigated. The passive scalar field is advected by a two-layer baroclinic turbulent flow which can generate various representative regimes in atmosphere and ocean. Much simpler and more tractable linear Ga...