The University of Michigan will research the physics of non-ideal effects in practical rotating detonation engines (RDEs) that impede the realization of theoretical detonation cycle efficiencies and operability. RDEs that use detonation-based compression are considered superior to the external compressor-based Brayton cycle engines because of their ability to use shock-based compression to increase pressure of the fluid in the combustor, which leads to a gain in thermal efficiency (pressure gain). Combined with conventional compressors, such devices promise significantly higher overall efficiencies compared to traditional cycles. RDEs and other similar variants for turbine engine applications have been studied for many decades, and several lab- and medium-scale devices have been built. The main issues that prevent large-scale and practical use of RDEs arise from the non-idealities associated with imperfect mixing and detonation structure. Currently, there are no design guidelines on how to overcome or account for these non-idealities. In this work, the project team will use detailed experimental measurements and computational tools to research the source or cause of such non-idealities from a fundamental physics point of view and link them to RDE performance. The goal of this work is to take a fundamental point of view and use detailed experiments and simulations to understand non-ideal effects and their contribution to loss in pressure gain.