Where the inertial / convective term is dominant?

The inertial or convection term is dominant in the laminar regime. Generally, the laminar flow occur when the fluid is viscous and when it is moving very slowly.

Laminar regime is characterized by the low momentum convection and the high momentum diffusion.

The laminar regime flow is basically occur at the low velocities. When the reynolds number is less than 1, then the fluid exhibited stokes. Then, the viscous force in the fluid deaminate the convection or inertial forces.