Subgrid modelling of Rayleigh-Taylor and Richtmyer-Meshkov instabilities in astrophysical contexts

• Applicant: Professor Marcus Brüggen, Ph.D.
• Subject Area: Astrophysics and Astronomy
• Term: from 2009 to 2013
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 97993990

• Final Report Year: 2013

Final Report Abstract

We have implemented a state-of-the-art subgrid model into the adaptive-mesh hydrodynamics code FLASH. It was tested against analytical solutions of test problems for the Rayleigh-Taylor (RT) and Richtmyer-Meshkov (RM) instability. Many of the RT and RM unstable modes that drive the evolution of underdense bubbles in stratified atmospheres evolve on scales that are far below the resolution limits of current simulations. The superposition of these unstable modes smears out the interface between the bubbles and the ambient medium, transforming them into clouds of mixed material that stay intact and expand as they rise in the stratified cluster medium. In a second sub-project we developed a new method to measure turbulence in hydrodynamical simulations in order to study the properties of turbulence in galaxy clusters. Some of the work proposed in our original grant proposal had already started before the grant started. This meant that we could go further than originally planned and explore additional aspects of turbulence in galaxy clusters. We are very pleased with the outcome of this work, which was transformative for our science, has resulted in substantial pieces of software and has gone well beyond our original plans. The numerical methodology presented here is likely to have applications in other areas of astrophysics where hydrodynamic modeling of RT instabilities is crucial, such as supernovae, supernova remnants, and galactic winds. It is clear that while many physical processes may play important roles in clusters and other environments, these can only be understood when carefully disentangled from the impact of subgrid turbulence.

Publications

• MNRAS 395, 2210 (2009)
  Brüggen, M., Scannapieco, E., Heinz, S.
  
• MNRAS 405, 1634 (2010)
  Scannapieco, E., Brüggen, M.
  
• A&A 529, A17 (2011)
  Vazza, F., Brunetti, G., Gheller, C., Brunino, R., Brüggen, M.
  
• MNRAS 418, 960 (2011)
  Vazza, F., Dolag, K., Ryu, D., Brunetti, G., Gheller, C., Kang, H., Pfrommer, C.
  
• A&A 544, 17 (2012)
  Vazza, F., Roediger, E., Brüggen, M.
  
• MNRAS 429, 799 (2013)
  Vazza, F., Eckert, D., Simionescu, A., Brüggen, M., Ettori, S.