Doppler Tomograms from Hydrodynamical Models of Dwarf Nova Disks

We present three-dimensional models of accretion disks in U Gem - like systems and calculate their Doppler tomograms. The tomograms are based on two different assumptions concerning the origin of line emission from the disk. The assumption of lines originating due to irradiation of the surface layer of the disk by the central source leads to a better agreement with observations. We argue that fully three-dimensional modelling is necessary to properly interpret the observed tomograms.