  We present simulations of the capabilities of the Next Generation Very Large
Array to image at high angular resolution substructures in the dust emission of
protoplanetary disks. The main goal of this study is to investigate the kinds
of substructures that are expected by state-of-the-art 3D simulations of disks
and that an instrument like the ngVLA, with its current design, can detect. The
disk simulations adopted in this investigation consist of global 3D
radiation-hydrodynamics models with embedded particles, the latter representing
dust grains. Our work shows that the ngVLA can detect and spatially resolve,
down to sub-astronomical unit scales in disks in nearby star forming regions,
the dust continuum emission at 3mm from azimuthal asymmetric structures, as
well as from weak rings and gaps produced in these models as a consequence of
the vertical shear instability (VSI). This hydrodynamical instability has been
proposed to generate turbulence in regions of weak coupling between the disk
gas and magnetic field, as well as to form vortices which may be preferred
locations of planetesimal formation.
