“…The characteristic features of these QPOs suggest that such oscillations are a diagnostic of the accretion processes in the inner regions of the accretion disks around the central compact objects, like shock oscillations in sub-Keplerian advective accretion disks (Chakrabarti & Titarchuk 1995, hereafter CT;Molteni, Sponholz, & Chakrabarti 1996, hereafter MSC; Kazanas, Hua, & Titarchuk 1997;Titarchuk, Lapidus, & Muslimov 1998;Chakrabarti & Manickam 2000, hereafter CM). The Galactic microquasar GRS 1915ϩ 105 shows several properties indicating that QPOs may be generated as the result of the oscillation of the hot, dense inner regions of BH accretion disks (Paul et al 1998;Muno, Morgan, & Remillard 1999;Yadav et al 1999;Rutledge et al 1999;Smith, Heindl, & Swank 2002). A numerical simulation by MSC revealed that for a shocked nonspherical advective BH accretion flow, if the inflow and cooling parameters are properly tuned, the postshock cooling time becomes comparable to the advection timescale from the shock.…”