2-D Rayleigh-Taylor Instability

This page contains recent results of 2-D Rayleigh-Taylor instability simulations performed with the FLASH code.

We have carried out 2 and 3-D Rayleigh-Taylor calculations as part of our validation program for the FLASH-1 code; the 2-D results shown here were obtained for an Atwood number of 1/3 (i.e., the ratio of the density of the heavier fluid to the density of the lighter fluid is 2:1). The initially planar interface was perturbed with a single-mode perturbations at t=0, at the midpoint of the domain. This calculation takes advantage of the AMR feature of the FLASH-1 code, exploiting up to 10 levels of adaptive mesh refinement.

The images show a narrow spike of dense fluid falling under the influence of gravity, and bubbles of light fluid rising up on the sides. The small features are the result of a Kelvin-Helmholtz instability at the interface of the fluids.

The above image shows the density field of the 2-D Rayleigh-Taylor simulation at a late stage in the calculation. The full domain of the computation is shown. With the 10 levels of refinement, the effective uniform grid resolution of this calculation is 16,384 x 4,096.

OB We can zoom in on the green rectangle marked above to reveal further detail:

Here, about 7% of the total domain is shown. Even at this resolution, the smallest details that FLASH tracked are not resolved in this image.

Zooming in further reveals even more detail:

At this resolution, each pixel represents about 2x2 zones.

We can look at the block structure for this portion of the domain to see how the AMR refined on the detail. In the image below, the block boundaries are drawn in blue. Each block contains 8x8 zones.

This calculation was performed by Kevin Olson with the FLASH code on the Cray T3E at the Pittsburgh Supercomputing Center.

All material on these pages is Copyright © 1999 (ASC) Flash Center.