This special issue is a compilation of some of papers presented at the conference. The papers were selected after a thorough review process and group together under the key topics listed above. It would be too exhaustive to give an overview of them here, however, some trends may be observed when comparing with the first PBM-conference edition. For example, one of the future prospects of the Hawaii conference, the routine analysis of particle-loaded complex flow systems, was clearly confirmed, resulting in numerous contributions in this area. The advancement in computing power has freed the path for this development. Also, the current use of PBM focuses on understanding and improving/optimising certain industrial/engineering processes that have been used for several decades. In these cases process measurements are an important aspect in terms of model calibration and solution methods for PBM are continually being investigated and improved.