The operational mode and stability of Rotating Detonation Combustors (RDCs) is largely impacted by the mixing quality due to their high operating frequencies and limited time before the subsequent wave passage. Due to the flashback hazard reactants in RDCs are commonly injected separately. This work presents the recently completed RDC at TU Berlin that was developed for the study of different injection schemes. High-speed pressure transducers in the annulus, as well as high-speed video of the detonation wave natural luminosity from the aft end of the RDC are employed simultaneously to investigate different operational modes. Results confirm the steady operation with in single wave, as well as two counter-rotating wave mode. The latter demonstrates complex, periodic lap-to-lap dynamics that indicate a weakening of the freely propagating waves, followed by re-strengthening after collision. Additionally, differences in velocity between waves leads to an amplitude modulation of the pressures measured in the annulus observed as beating. The mean natural detonation wave luminosity profile due to high temperature emission from H_2O in the RDC annulus during steady single wave operation shows an interesting characteristic with a steep increase in luminosity, followed by much longer trailing tail of decreasing luminosity that extends throughout half the annulus perimeter.
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