  We report on the eclipse mapping analysis of an ensemble of light curves of
the dwarf nova V2051 Oph with the aim to study the spatial distribution of its
steady-light and flickering sources. The data are combined to derive the
orbital dependency of the steady-light and the flickering components at two
different brightness levels, named the 'faint' and 'bright' states. The
differences in brightness are caused by long-term variations in the mass
transfer rate from the secondary star. Eclipse maps of the steady-light show
enhanced emission along the ballistic stream trajectory, in a clear evidence of
gas stream overflow. We identify two different and independent sources of
flickering in V2051 Oph. Low-frequency flickering arises in the overflowing gas
stream and is associated to the mass transfer process. It maximum emission
occurs at the position of closest approach of the gas stream to the white
dwarf, and its spatial distribution changes in response to variations in mass
transfer rate. High-frequency flickering originates in the accretion disk,
showing a radial distribution similar to that of the steady-light maps and no
evidence of emission from the hot spot, gas stream or white dwarf. This disk
flickering component has a relative amplitude of about 3 per cent of the steady
disk light, independent of disk radius and brightness state. If the disk
flickering is caused by fluctuations in the energy dissipation rate induced by
MHD turbulence, its relative amplitude lead to a viscosity parameter alpha=
0.1-0.2 at all radii for the quiescent disk. This value seems uncomfortably
high to be accommodated by the disk instability model [abridged].
