The study of the internal component geometries (i.e. perforated elements) is relevant for the acoustic performance optimisation
of a silencer. During the design phase, the evaluation of the properties of a silencer is performed by numerical analysis.
In the literature, there is a lack of general guidelines and comparisons among different modelling strategies. So, in this study,
the influence of grid type (i.e. trimmed vs tetrahedral) on the numerical prediction of the flow inside a reactive silencer is
analysed. Moreover, using a porous baffle interface to model the perforated pipe is investigated, searching for a faster and
easier way to model perforated elements. The simulations are carried out with the commercial CFD software STAR-CCM+.
The comparison of the obtained axial velocity with a literature case study assesses the numerical model reliability. The
analysis highlights that velocity and pressure predicted with both the mesh typologies does not significantly differ, but the
trimmed mesh allows to save cells number, reducing the computational cost. Instead, obtain a reliable flow description using
the porous baffle interface is strictly correlated to the settings of the resistance coefficient. This assumption does not provide
accurate results for the analysed perforated pipe. On the other hand, using a simplified model allows to easily perform a
comparison between different muffler geometries, as the holes have not to be drowned and meshed after each modification.
