Adaptation to Eulerian Tracers
The following example illustrates the advantages solution-adaptive
grid generation methods. Three simulations were run to calculate concentrations
of Eulerian tracers. Simulation domain extended 3 degrees in the x-direction
and 2 degrees in the y-direction. The model was initialized with
an ideal uniform flow in the x-direction. Along with Eulerian tracers a
stream of particles was also released form the source in the Lagrangian
mode. The adaptation criteria was set to the particle locations, which
in essence is the plume center-line. All the initial conditions and the
boundary conditions were identical for the three simulations. The only
difference was in the initial grid resolution. The simulations were run
for 12 hours. The following table gives the characteristics of the grids
used in the three simulations and the CPU time.
| RUN |
RESOLUTION (km) |
CELLS |
CPU (s) |
| Coarse |
2.94 - 30.63 |
478 |
11362.665 |
| Global |
3.64 - 9.75 |
3634 |
92062.074 |
| Adaptation |
3.0 - 30.63 |
478 (initial)-1410 (final) |
28411.055 |
Animation
A. Sarma, N. Ahmad, D. Bacon, Z. Boybeyi, T. Dunn, M.
Hall and P. Lee, 1999: Application of Adaptive Grid
Refinement to Plume Modeling. Accepted for Air Pollution 99.
July 27-29, San Francisco, California.
ahmad@apo.saic.com
sarma@apo.saic.com