Evolution of the  density distribution in the equatorial plane computed with the radiation hydrodynamic model after the line-driven force from the companion-facing hemisphere was artificially switched off. The initial state (the uppermost left panel) corresponds to the steady-state solution depicted in Fig. 4. The bottom right panel captures the new nearly steady-state solution. The white index in the upper right corner of the each panel indicates an evolutionary time expressed in the units of the orbital periods. The red cross and asterisk show the position of the black hole and the centre of the supergiant, resp.