Long time-scale variability in GRS1915+105

We present very high resolution hydrodynamical simulations of accretion discs in black hole X-ray binaries accreting near the Eddington limit. The results show that mass loss, irradiation and tidal interactions all have a profound effect on the observed behaviour of long period X-ray transients. In particular, the interplay of all of these effects in the outer regions of the accretion disc is able to drive long time-scale (weeks to years) variability is these objects, and is a possible origin for some of the extreme variability of GRS1915+105.