ABSTRACT We use numerical hydrodynamics simulations to study line-driven winds launched from an accreting α-disc. Building on previous work where the driving radiation field is static, we compute a time-dependent flux local, variable accretion rate of disc. find that prior establishment steady state in disc, variations $\sim 15{{\ \rm per\ cent}}$ disc luminosity correlate with ∼ 2–3 mass wind....

The nonlinear dynamics of a warped accretion disc is investigated in the important case of a thin Keplerian disc with negligible viscosity and self-gravity. A one-dimensional evolutionary equation is formally derived that describes the primary nonlinear and dispersive effects on propagating bending waves other than parametric instabilities. It has the form of a derivative nonlinear Schrödinger ...

We consider the alignment torque between a spinning black hole and an accretion disc whose angular momenta are misaligned. This situation must hold initially in almost all gas accretion events on to supermassive black holes, and may occur in binaries where the black hole receives a natal supernova kick. We show that the torque always acts to align the hole’s spin with the total angular momentum...

We present an extension of the King et al. [1] model for the flickering of black hole accretion discs by taking proper account for the thermal properties of the disc. First we develop a one-dimensional, vertically averaged, one-zone model for an optically thick accretion disc and study the temporal evolution. This limits the current model to the so-called high/soft state, where the X-Ray spectr...

Accretion disc turbulence is investigated in the framework of the shearing box approximation. The turbulence is either driven by the magneto-rotational instability or, in the non-magnetic case, by an explicit and artificial forcing term in the momentum equation. Unlike the magnetic case, where most of the dissipation occurs in the disc corona, in the forced hydrodynamic case most of the dissipa...

The non-axisymmetric features observed in the discs of dwarf novae in outburst are usually considered to be spiral shocks, which are the non-linear relatives of tidally excited waves. This interpretation suffers from a number of problems. For example, the natural site of wave excitation lies outside the Roche lobe, the disc must be especially hot, and most treatments of wave propagation do not ...