Time evolution for a parameter study of various power-law exponents (β) and normalisations (ρ₀) of the assumed accretion flow density distribution (see legend and Eq. 1), as well as stellar wind velocities v_w. Shown are cuts through the density in the orbital plane at a time of 530 days before pericentre (panels a–c, same colour scale as in Fig. 1a–d; the white cross refers to the position of the BH), the mass transfer rate through the inner boundary (panel d), the variation of the electron number density of the accretion flow along the orbital path of S2 (panel e), and the light curves of excess X-ray emission (panel f). Time is given relative to the epoch of pericentre passage. The dotted magenta lines denote the accuracy of roughly a factor of two of the Baganoff et al. (2003) measurement.