Numerical Simulations Reveal the Origin of QPOs in Black Hole Candidates
  We present results of various types of numerical simulations of black hole accretion disks and find that those flows which are relatively non-dissipative and which contain accretion shocks are the best candidates so far. The power density spectra (PDS) reveal the aspects which are similar to what are observed in black hole candidates. 
Sandip K. Chakrabarti