22 research outputs found
On adaptive BDDC for the flow in heterogeneous porous media
We study a method based on Balancing Domain Decomposition by Constraints
(BDDC) for a numerical solution of a single-phase flow in heterogenous porous
media. The method solves for both flux and pressure variables. The fluxes are
resolved in three steps: the coarse solve is followed by subdomain solves and
last we look for a divergence-free flux correction and pressures using
conjugate gradients with the BDDC preconditioner. Our main contribution is an
application of the adaptive algorithm for selection of flux constraints.
Performance of the method is illustrated on the benchmark problem from the 10th
SPE Comparative Solution Project (SPE 10). Numerical experiments in both 2D and
3D demonstrate that the first two steps of the method exhibit some numerical
upscaling properties, and the adaptive preconditioner in the last step allows a
significant decrease in number of iterations of conjugate gradients at a small
additional cost.Comment: 21 pages, 7 figure
Simulation of the 2009 Harmanli fire (Bulgaria)
We use a coupled atmosphere-fire model to simulate a fire that occurred on
August 14--17, 2009, in the Harmanli region, Bulgaria. Data was obtained from
GIS and satellites imagery, and from standard atmospheric data sources. Fuel
data was classified in the 13 Anderson categories. For correct fire behavior,
the spatial resolution of the models needed to be fine enough to resolve the
essential micrometeorological effects. The simulation results are compared to
available incident data. The code runs faster than real time on a cluster. The
model is available from openwfm.org and it extends WRF-Fire from WRF 3.3
release.Comment: 8 pages, 2 tables, 5 figures. 8th International Conference on
Large-Scale Scientific Computations, June 6-10, 2011, Sozopol, Bulgari