  Recent progress in realistic simulations of solar convection have given us an
unprecedented opportunity to evaluate the robustness of solar interior
structures and dynamics obtained by methods of local helioseismology. We
present results of testing the time-distance method using realistic
simulations. By computing acoustic wave propagation time and distance relations
for different depths of the simulated data, we confirm that acoustic waves
propagate into the interior and then turn back to the photosphere. This
demonstrates that in the numerical simulations properties of acoustic waves
(p-modes) are similar to the solar conditions, and that these properties can be
analyzed by the time-distance technique. For the surface gravity waves
(f-mode), we calculate perturbations of their travel times, caused by localized
downdrafts, and demonstrate that the spatial pattern of these perturbations
(representing so-called sensitivity kernels) is similar to the patterns
obtained from the real Sun, displaying characteristic hyperbolic structures. We
then test the time-distance measurements and inversions by calculating acoustic
travel times from a sequence of vertical velocities at the photosphere of the
simulated data, and inferring a mean 3D flow fields by performing inversion
based on the ray approximation. The inverted horizontal flow fields agree very
well with the simulated data in subsurface areas up to 3 Mm deep, but differ in
deeper areas. Due to the cross-talk effects between the horizontal divergence
and downward flows, the inverted vertical velocities are significantly
different from the mean convection velocities of the simulation dataset.
