  Stars with masses above 1.6 solar masses generally possess convective cores
and radiative envelopes, which allows the propagation of outward-travelling
internal gravity waves. We have studied the generation and propagation of IGWs
in such stars using two-dimensional, fully nonlinear hydrodynamical simulations
with realistic stellar reference states from the one-dimensional stellar
evolution code, Modules for Stellar Astrophysics. Compared to previous similar
works, this study utilises radius-dependent thermal diffusivity profiles for 5
different stellar masses at the middle of main sequence: 3 - 13 solar masses.
From the simulations, we find that the surface perturbations are larger for
higher masses, but no noticeable trends are observed for the frequency slopes
with different stellar masses. The slopes are also similar to the results from
previous works. We compare our simulation results with stellar photometric data
from a recent survey and find that for frequency intervals above 8 microHz,
there is a good agreement between the temperature frequency slopes from the
simulations and the surface brightness variations of these observed stars,
indicating that the brightness variations are caused by core-generated IGWs.
