This Special Issue will publish selected papers from the 15th OpenFOAM Workshop June 22-25 2020 in Arlington Virginia USA. The workshop is hosted by the Crofton Department of Aerospace and Ocean Engineering at Virginia Tech.During this community driven event conference presentations and poster sessions will be held and work in progress is gladly seen as well. In addition to the conference aspect trainings on OpenFOAM technology and other related software tools are held mostly from users for user