For over a decade, we have been focusing on physics-based modeling of wildland and wildland-urban interface (WUI) fires. These are multiphysics events in which numerous physical and chemical processes, such as combustion, gravity-driven flows, turbulence, solid fuel pyrolysis, thermal radiation, and convective heating, interact with one another. We solve mathematical (differential) equations that capture these coupled processes and so describe the fire behavior using physics-based modeling. Because wildland and WUI fires have a wide range of time and three-dimensional scales, we do massive computations using parallel processing to resolve the scales with appropriate accuracy. We have had several projects funded by various federal agencies in the area of wildland and WUI fires: Exploring the influence of convection and thermal radiation on pyrolysis, ignition and burning behavior of live leaves; Investigation of the shrub fire dynamics and merging of individual shrub fires; and determination of ignition propensity by firebrands in wildland-urban interface.

Another major research activity in our group concerns dusty plasmas (a.k.a. complex plasmas), which contain nano- to micro-meter size solid particles in addition to ions and electrons. Dusty plasmas are found in space and processing industry where plasmas are used. A dust grain collects ions and electrons from the plasma and gains a net electric charge that randomly fluctuates over time.  A project funded by NSF has been on description of this type of fluctuation, which is an intrinsic noise inherent in the actual mechanism responsible for the evolution of the system and cannot be switched off.  We recently showed through stochastic modeling that the charge fluctuations may become metastable when the effects of the secondary electron emission from the grains are included. Metastability of fluctuations is manifested by the passage of the grain charge between two macrostates.