  Global hydrodynamic simulations of internal solar dynamics have focused on
replicating the conditions for solar-like differential rotation and meridional
circulation using the results of helioseismic inversions as a constraint.
Inferences of meridional circulation, however, have provided controversial
results showing the possibility of one, two, or multiple cells along the
radius. To resolve this controversy and develop a more robust understanding of
global flow regimes in the solar interior, we apply a "forward-modeling"
approach to the analysis of helioseismic signatures of meridional circulation
profiles obtained from numerical simulations. We employ the global acoustic
modeling code GALE to simulate the propagation of acoustic waves through
regimes of mean mass flows generated by global hydrodynamic and
magnetohydrodynamic models: EULAG, the Pencil Code, and the Rayleigh code.
These models are used to create synthetic dopplergram data products, used as
inputs for local time-distance helioseismology techniques. Helioseismic
travel-time signals from solutions obtained through global numerical
simulations are compared directly with inferences from solar observations, in
order to set additional constraints on global model parameters in a direct way.
We show that even though these models are able to replicate solar-like
differential rotation, the resulting rotationally-constrained convection
develops a multi-cell global meridional circulation profile that is measurably
inconsistent with local time-distance inferences of solar observations.
However, we find that the development of rotationally-unconstrained convection
close to the model surface is able to maintain solar-like differential
rotation, while having a significant impact on the helioseismic travel-time
signal, replicating solar observations within one standard deviation of the
error due to noise.
