QPOs from Radial and Vertical Oscillation of Shocks in Advective   Accretion Flows
  We present results of several numerical simulations of two dimensional advective flows which include cooling processes. We show that the computed light curve is similar to the $\chi$ state in GRS 1915+105. The power density spectrum (PDS) also shows presence of QPOs near the break frequency. 
Sandip K. Chakrabarti, K. Acharyya and D. Molteni