that the quasi-periodic variation of the shock location and the photon fluxes from post-shock disc and outflow are characterized by the fundamental frequency $\nu_{\rm fund} = 3.7$ Hz which is followed by multiple harmonics. The first few prominent harmonic frequencies are $7.4$ Hz ($\sim 2 \times \nu_{\rm fund}$), $11.2$ Hz ($\sim 3 \times \nu_{\rm fund}$) and $14.2$ Hz ($\sim 4 \times \nu_{\rm fund}$). This suggests that the dynamics of the inner part of the disc the post-shock disc and emitted fluxes are tightly coupled. In order to understand the generic nature of the above findings, we carried out another simulation with different input parameters. The results are shown in Figure 6, where we use $r_{\rm inj} = 50.4~r_g$, $v_{\rm inj} = -0.06436$, $a_{\rm inj} = 0.06328$, $\lambda_{\rm inj} = 1.61$ and $\alpha = 0.013$, respectively. The solutions are obtained similar to the previous case, first a steady state inviscid solution is obtained and then the viscosity is turned on. The corresponding Fourier spectra of shock oscillation and power spectra of radiative fluxes are presented in the [*top*]{}, [*middle*]{} and [*bottom panel*]{}, respectively. The obtained frequencies for quasi-periodic variations are $2.9~{\rm Hz}~{\rm \bf }~(\bf \nu_{\rm \bf fund})$, $5.6$ Hz ($\sim 2 