  In modern transport systems, passengers' comfort is greatly influenced by
flow-induced noise. In this study we investigate a generic deep cavity with an
overhanging lip, mimicking a door gap in a vehicle, that is overflowed by air
at two different free stream velocities, 26.8m/s and 50m/s. The turbulent
boundary layer and the acoustic waves interact with the cavity's geometry and
form a strong feedback mechanism. In the present work, we focus on the details
of the compressible turbulent flow structures and their variations concerning
the velocity, the boundary layer as well as the domain dimensionality for a
later acoustic simulation within a hybrid aeroacoustic workflow. Furthermore,
we verify the feasibility of reducing the acoustic computational domain from 3D
to 2D for this application by conducting a coherence study of acoustically
active flow structures in the spanwise direction. The role of the
three-dimensional Taylor-G\"ortler vortices from the recirculation regarding
the vortex formation and the vortex-edge interaction was also evaluated.
Remarkably for the lower approaching velocity (26.8m/s), we found a special
vortex-edge interaction, namely an alternating sequence of complete clipping
and a subsequent partial escape. Lastly, we assigned previous unknown peaks in
the pressure spectrum to their corresponding mechanisms.
