Vortices influenced by topography

Norsk talande vitjarar:

This project is part of the Ph.D. thesis of Halvard Moe. The purpose is to try to understand some of the complex interaction between vortices and topography as seen outside the cost of Norway. The equations in use is the two primitive equations in one or two layers. We are simulating the behavior of a dipole approaching a step in the bottom topography. As initial condition we take the Lamb dipole. This configuration will in presence of the Coriolis force move in a straight line on a flat bottom. When an obstacle in the bottom topography is produced the motion is altered. This could qualitatively be understood by examining the Potential vorticity equation, but in order to get the details this should be modeled in some more thorough fashion. We have both done numerical and experimental simulations in case of a barotropic fluid. Qualitatively we see the same behavior. The experiments were performed in Eindhoven, The Netherlands, while visiting the Vortex Dynamics Group. In case of a layered fluid we have only done computer simulations.