Internal waves in aquariums with characteristic corners

We give a precise microlocal description of the singular profile that forms in the long-time propagation of internal waves in an effectively two-dimensional aquarium. We allow domains with corners, such as polygons appearing in the experimental set ups of Maas et al. This extends the previous work of Dyatlov--Wang--Zworski arXiv:2112.10191, which considered domains with smooth boundary. We show that in addition to singularities that correspond to attractors in the underlying classical dynamics, milder singularities propagate out of the corners as well.