  We present simulations of the interferometric visibilities of Herbig Ae star
disks. We investigate whether interferometric measurements in the 10 micrometer
atmospheric window are sensitive to the presence of an increased scale height
at the inner disk edge, predicted by recent models. Furthermore, we investigate
whether such measurements can discriminate between disks with a ``flaring''
geometry and disks with a ``flat'' geometry. We show that both these questions
can be addressed, using measurements at a small number of appropriately chosen
baselines. The classification of Herbig Ae stars in two groups, based on the
appearance of the spectral energy distribution (SED), has been attributed to a
difference in disk geometry. Sources with a group I SED would have a flaring
outer disk geometry, whereas the disk of group II sources is proposed to be
flat (or ``self-shadowed''). We show that this hypothesis can be tested using
long-baseline interferometric measurements in the micrometer atmospheric
window.
