Large-Eddy Simulation of Symmetric Instability

Symmetric instability can develop in the ocean and atmosphere when the potential vorticity is less than zero. In this large-eddy simulation, a density front in the upper ocean was forced by cooling the surface of the ocean with a constant heat flux, which also acts to decrease the potential vorticity. As symmetric instability develops, the flow (vectors) becomes nearly aligned with the isopycnal surfaces (color). Eventually, the vertical shear associated with symmetric instability becomes unstable to a secondary Kelvin-Helmholtz instability which can be clearly seen when the green isopycnal sheet rolls up into multiple billows. Taylor and Ferrari (2009) showed that this secondary shear instability is responsible for equilibrating symmetric instability, and Taylor and Ferrari (2010) examined the role of forced symmetric instability in generating turbulence at upper ocean fronts - animation credit: John Taylor, Ferrari Group, MIT

Category:

Science & Technology

Tags:

• Symmetric
• Instability