Skip to main content
Email Print Share

Bursts of Stellar Turbulence (Image 1)

A 3-D mixing layer between two fluids of different densities in a gravitational field.

A slide depicting a 3-D mixing layer between two fluids of different densities in a gravitational field. Known as a Rayleigh-Taylor instability--a type of turbulent mixing that occurs due to gravity, when a heavy gas is on top of a lighter one--this mixing plays an essential role in stellar convection and is being studied in this context to help devise and validate statistical models of turbulent fluid mixing at the boundaries of convection zones in stars. [Image 1 of 4 related images. See Image 2.]

More about this Image
Paul Woodward and (David Porter, astrophysicists from the University of Minnesota's Laboratory for Computational Science and Engineering LCSE), are using the Pittsburgh Supercomputing Center's (PSC) Cray XT3 and PSC-developed software to run interactive simulations of turbulence.

The main focus of Woodward and Porter's research is astrophysical flows--specifically, using large-scale supercomputer simulations to understand and model turbulent convection in stars. Their long-term goal is to accurately simulate in detail, the turbulent dynamics of an entire giant star--stars similar to the sun. Woodward and Porter have been using small-scale turbulence to help identify parameters with which to build an accurate model of turbulence on a large scale.

It was their work on small-scale turbulence that led to a significant breakthrough when in January 2007, they used the entire system--4,096 XT3 processors (plus eight input/output nodes)--to simulate turbulent shear between two fluids. They used a computational grid of 5763 cells, fine enough to resolve the small-scale turbulence they wanted to understand--a run that would take weeks or months on an average cluster. With performance of 2.32 gigaflops (billions of calculations per second) on each XT3 processor, 9.5 teraflops overall, the run of 6,000 time steps was completed in 7.7 minutes.

To read more about this research, see "Bursts of Stellar Turbulence" from the PSC Projects in Scientific Computing 2007 Annual Report. [Numerical simulations were performed on the Cray XT3 at the Pittsburgh Supercomputing Center and the visualization of the output data was performed at the LCSE on equipment purchased with support of National Science Foundation grants CNS 04-21423 and CNS 07-08822.] (Date of Image: 2007)

Credit: Prof. Paul Woodward, Laboratory for Computational Science and Engineering, University of Minnesota

General Restrictions:
Images and other media in the National Science Foundation Multimedia Gallery are available for use in print and electronic material by NSF employees, members of the media, university staff, teachers and the general public. All media in the gallery are intended for personal, educational and nonprofit/non-commercial use only.

Images credited to the National Science Foundation, a federal agency, are in the public domain. The images were created by employees of the United States Government as part of their official duties or prepared by contractors as "works for hire" for NSF. You may freely use NSF-credited images and, at your discretion, credit NSF with a "Courtesy: National Science Foundation" notation. Additional information about general usage can be found in Conditions.

Also Available:
Download the high-resolution TIF version of the image. (36 MB)

Use your mouse to right-click (Mac users may need to Ctrl-click) the link above and choose the option that will save the file or target to your computer.