Resource Units Per Run

The following is a list of specific projects to be done along with estimates of the number of RU needed for each part. These estimates are based on testing done on the OSC Origin 2000 and on the NCSA Origin 2000 cluster.

Specifically, this project plans to

• Forge a link with earlier, 2D axisymmetric hydrodynamic simulations, by exploring for a small subset of earlier 2D simulations those modes of instability that are suppressed in 2D, but which are expected on the basis of linear stability analysis to dominate the formation of internal jet structure in 3D; see the next section for further comments. For these axisymmetric relativistic jets in 3D cartesian coordinates we request a total of three such runs at 150 RU per run. The total requested is 450 RU for this part.
• Study the nonlinear development of instability for a small subset of earlier 2D simulations by perturbing the flow with a periodic driving force designed to excite the most unstable modes suggested by linear stability analysis. This project will study the nonlinear development of instability in Cartesian coordinates of some of the axisymmetric simulations. We request a total of three such runs at 150 RU per run. The total requested is 450 RU for this part.
• Study the development of internal jet structure, and its subsequent evolution, due to the interaction of a jet with an ambient density inhomogeneity - an idealization of the interaction of the jet with an interstellar cloud or gradient in the diffuse interstellar medium. The deflection of initially axisymmetric jets in Cartesian coordinates will begin to address the important issue of which mechanisms are most viable for deflection, help us to understand the jet's response to bending, the possible maintenance of the jet's integrity and the development of its internal structure. We request a total of three such runs at 150 RU per run. The total requested is 450 RU for this part.
• Study the development of internal jet structure and its subsequent evolution due to precession of the jet inflow - a process strongly suggested by the S-symmetric kiloparsec-scale sources, and likely to occur in situations with multiple galactic nuclei. We hope to extract information on the kinematics of high brightness structures in the complex evolving flow. We have made some preliminary runs with coarse resolution of the evloving precessing jet, the results of which are illustrated in Fig. 2 . Due to the complexity of the flow induced by the precession this will be a single high resolution run of the code. We estimate that 500 RU will be needed for this.

The total requested RU for the project is thus: 1850 RU.