click on one of the images to learn about my research.  
 

Maestro: A Low Mach Number Stellar Hydrodynamics Code

in collaboration with CCSE/LBL

 low Mach number modeling
We have developed a new stratified low Mach number hydrodynamics algorithm, allowing for finite-amplitude density/temperature fluctuations while filtering soundwaves.
 
 		  
 
bubbles

Reacting Buoyant Bubbles

in collaboration with CCSE/LBL and Jonathan Dursi
We are performing large scale, fully resolved studies of burning rising bubbles in both two and three dimensions in conditions appropriate to Type Ia supernovae.
 
 		  
 

3-D Reactive Rayleigh-Taylor

in collaboration with CCSE/LBL and Stan Woosley (UCSC)


 3-D RT
Three-dimensional direct numerical simulations of carbon flames in Type Ia supernovae undergoing the Rayleigh-Taylor instability and the transition to turbulence.
 
 		  
 
Reactive Rayleigh-Taylor Instability

Reactive Rayleigh-Taylor Instability: the Transition to Distributed Burning

in collaboration with CCSE/LBL and Stan Woosley (UCSC)
Direct numerical simulations of Rayleigh-Taylor unstable flames in Type Ia supernovae. We simulate a range of densities capturing the transition from the flamelet regime to the distributed burning regime. These are the first multi-dimensional simulations to show this transition directly.
 
 		  
 

SNe II Mixing

in collaboration with Stan Woosley (UCSC)

 SN II Mixing
Two-dimensional, spherical AMR calculations of the post-shock mixing.
 
 		  
 
X-ray burst gallery

Helium Detonations on
Neutron Stars

(my thesis)
 

in collaboration with the Flash Center
Two-dimensional calculations of the dynamics of the explosion from my thesis. We follow the detonation wave as it propagates 2 km across the surface of the neutron star.
 
 		  
 

Flame-Vortex Interactions

in collaboration with the Flash Center

 flame-vortex interactions
Studies as to whether the interaction of a thermonuclear flame with a vortex pair can locally quench the flame.

 

Other research:

FLASH Code

I am one of the developers of the FLASH Code (described in detail in our code paper), a parallel, AMR hydrodynamics code. FLASH solves the compressible Euler equations and can include self-gravity. We won a Gordon Bell prize in 2000 for a cellular detonation with FLASH, run on 6420 processors of the ASCI Red computer. FLASH is freely downloadable.

 

Computational Hydrodynamics

I am also working on a simple prototyping code to test out different CFD algorithms, concentrating at the moment at understanding the behavior of split vs. unsplit algorithms. Some of this is done in pyro. It is mostly a toy code, not intended for production jobs, but mainly to try different ideas out. This hydrodynamics code is written in python/C, and is available for download here.

 

1-D Flame Models

Some simple C/O flame models (using an unscreened Caughlan & Fowler 1988 reaction rate) are available for comparison. These are the same models used in Dursi et al. 2003 (submitted).

 

I/O

Previously, I worked a lot on Parallel I/O for FLASH. I've summarized some of this in a general parallel I/O tutorial.

 

Computer Resources

Presently, I use the following computers:

the jaguar XT3 at the National Center for Computational Sciences (NCCS)

the SGI Altix Columbia machine at the NASA Advanced Supercomputing (NAS) Division of NASA/Ames

the systems at the National Energy Research Science Computing Center

I also have a small cluster, Homer

 

Collaborators:

Most recently, I have been collaborating with Ann Almgren, John Bell, Marc Day, and Charles Rendleman at the Center for Computational Science and Engineering at Lawrence Berkeley Laboratory.

Jonathan Dursi and I frequently collaborate on problems involving astrophysical flames.

I am part of the SciDAC-2 Computational Astrophysics Consortium.

updated Jan, 1, 2007

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