In the first frame of the "Prograde" movie shown here, a number of green test particles have been lined up along the major axis of one of Andalib's nonaxisymmetric disk models. Thereafter the particles are followed as they move along equatorial-plane streamlines of the flow, as viewed in a frame of reference that is rotating with the overall pattern speed of the nonaxisymmetric disk configuration. The illustrated flow is entirely prograde and largely differential, but there is a small volume near the center of the configuration that is moving harmonically.
The similarity between the flow in this steady-state configuration -- which has been derived using a self-consistent-field technique -- and the differential flow that has developed naturally from one of our fully three-dimensional, hydrodynamical simulations is striking!
|Four Andalib Models|
The animation sequence labeled "Four Andalib Models" illustrates the internal flow of four of Andalib's compressible disks with nonaxisymmetric structures. In addition to the model (P) which also has been displayed in the "Prograde" movie, above, the animation sequence illustrates: one model with fully retrograde internal motions (R); one model with vortices sandwiched between separate regions of prograde and retrograde flow (V); and a common-envelope binary (dumbbell-shaped) configuration (D). Andalib's work demonstrates that model "P" is just one among a series of compressible models with nontrivial internal flows that defines a smooth elliptical-dumbbell-binary sequence. As we have argued in a paper presented at the "Numerical Astrophysics 1998" conference in Tokyo ( Tohline, Cazes, and Cohl 1999), we therefore suspect that the final triaxial configuration that forms as a result of the two-armed, spiral-mode instability sits on an analogous (3D) sequence and that, if it is cooled slowly, it will evolve along the sequence to a common-envelope binary configuration such as the one illustrated here by model "D".
|Producer||Visualization Directors||Scientific Director|
|Joel E. Tohline||
John E. Cazes
Howard S. Cohl
This work has been supported, in part, by the U.S. National Science Foundation through grant AST-9528424 and, in part, by grants of high-performance-computing time at the San Diego Supercomputer Center and through the PET program of the NAVOCEANO DoD Major Shared Resource Center in Stennis, MS.