  The complexity of the ISM is such that it is unlikely that star formation is
initiated in the same way in all molecular clouds. While some clouds seem to
collapse on their own, others may be triggered by an external event such as a
cloud/flow collision forming a gravitationally unstable enhanced density layer.
This work tests cloud-cloud collisions as the triggering mechanism for star
formation in the Serpens Main Cluster as has been suggested by previous work. A
set of smoothed particle hydrodynamics (SPH) simulations of the collision
between two cylindrical clouds are performed and compared to (sub)millimetre
observations of the Serpens Main Cluster. A configuration has been found which
reproduces many of the observed characteristics of Serpens, including some of
the main features of the peculiar velocity field. The evolution of the velocity
with position throughout the model is similar to that observed and the column
density and masses within the modeled cloud agree with those measured for the
SE sub-cluster. Furthermore, our results also show that an asymmetric collision
provides the ingredients to reproduce lower density filaments perpendicular to
the main structure, similar to those observed. In this scenario, the formation
of the NW sub-cluster of Serpens can be reproduced only if there is a
pre-existing marginally gravitationally unstable region at the time the
collision occurs. This work supports the interpretation that a collision
between two clouds may have been the trigger of the most recent burst of star
formation in Serpens. It not only explains the complicated velocity structure
seen in the region, but also the temperature differences between the north (in
"isolated" collapse) and the south (resulting from the shock between the
clouds). In addition it provides an explanation for the sources in the south
having a larger spread in age than those in the north.
