  Confluent cell monolayers and epithelia tissues show remarkable patterns and
correlations in structural arrangements and actively-driven collective flows.
We simulate these properties using multiphase field models. The models are
based on cell deformations and cell-cell interactions and we investigate the
influence of microscopic details to incorporate active forces on emerging
phenomena. We compare four different approaches, one in which the activity is
determined by a random orientation, one where the activity is related to the
deformation of the cells and two models with subcellular details to resolve the
mechanochemical interactions underlying cell migration. The models are compared
with respect to generic features, such as solid-to-liquid phase transitions,
cell shape variability, emerging nematic properties, as well as vorticity
correlations and flow patterns in large confluent monolayers and confinements.
All results are compared with experimental data for a large variety of cell
cultures. The appearing qualitative differences of the models show the
importance of microscopic details and provide a route towards predictive
simulations of patterns and correlations in cell colonies.
