inj} = 50.4$, $v_{\rm inj} = -0.06436$, $a_{\rm inj} = 0.06328$, $\lambda_{\rm inj} = 1.63$ and $\alpha = 0.011$ respectively. Note that persistent shock oscillation takes place over a large time interval, with the oscillation amplitude $\sim 3 r_g$. This phenomenon exhibits the emission of non-steady radiative flux which is nicely accounted as quasi-periodic variation commonly seen in many black hole candidates [@cm00; @rm06]. Subsequently, periodic mass ejection also results from the vicinity of the gravitating objects as a consequence of the modulation of the inner part of the disc due to shock oscillation.

To understand the correlation between the shock oscillation and the emitted photon flux from the inner part of the disc, we calculate the Fourier spectra of the quasi-periodic variation of the shock front and the power spectra of bremsstrahlung flux for matter resides within the boundary of post-shock region as well as outflow with resultant velocity $v>0$. The obtained results are shown in Figure 5, where the [*top panel*]{} is for shock oscillation, [*middle panel*]{} is for photon flux variation from post-shock disc and [*bottom panel*]{} is for photon flux variation of outflowing matter, respectively. Here, the input parameters are same as Figure 4. We find 