Auckland Islands Simulation

This page describes a numerical simulation of gravity waves over the Aucklin Islands generated by the winds profiles depicted below.

Computational Domain

The layout of the of the simulation is shown in the figure below. Note the boundaries at lines of constant longitude and latitude.
domain

Just the computational domain is shown in the figure below. In this plot, the surface has been interpolated to rectangular coordinates.

surface

The mesh is clustered in both horizontal directions in order to achieve 1000 x 1000 meter spacing over the Islands. Moderatley weak stretching is used so that the resolution at the boundaries is ~4000 x 4000 meters. The domain extends to an altitude of 98 km and uses uniform vertical spacing of 200 m. A total of 336 x 336 x 480 mesh points are used. Sponge layers are used on all external boundaries in order to absorb outgoing waves.

Wind and Thermodynamic Profiles

winds

magnitude

direction

direction

temperature

N_sq

N_sq

Initial Wind Condition

To avoid a high response form the initial winds imposition, increased sponge and filter strengths were used to combat numerical errors. The simulation was then restared with lower, more resonable values to minimize effects to the solution. A sound wave, visually evident in the solution, is a numerical result of this approach. Further study with a mean wind evolution in time is likely to follow.

Animation of vorticity magnitude in the xz plane at the position y = -10 km






Animation of w' in the xz plane at the position y = -10 km






Animation of w' in the xy plane at an altitlde of 15 km






Animation of w' in the xy plane at an altitude of 50 km






Animation of vorticity magnitude in the xy plane at an altitude of 78 km






Animation of w' in the xy plane an altitude of 78 km