  Results of nonradial, nonadiabatic pulsation calculations on hydrogen-rich
white dwarf models are presented. In contrast to earlier attempts, the modeling
builds on hydrodynamically simulated convective surface layers supplemented
with standard interior models. Based on our stellar models and despite of
various simple attempts to couple convection and pulsation we could not
reproduce theoretically the presently adopted location of the observed blue
edge of the ZZ Ceti variables. When the convective efficiency is high enough we
found a sensitive dependence of the stability properties of the g-modes on the
pulsational treatment of shear within the convection zone.
