A three-dimensional numerical simulation of rotating detonation engine (RDE) with hollow combustor is performed to analyze wave structure evolution systematically. Wave structure evolution is classified into four categories, namely two-wave collision (counter rotating waves), abscission of detonation tail, and shock wave to detonation transition. Two-wave collision consists of symmetric detonation collision, asymmetric detonation collision, and detonation/shock collision. Two symmetric detonation waves turn into shock waves after collision. Collision of asymmetric detonation waves creates single detonation wave. The detonation/shock collision decreases the detonation wave intensity. Abscission of detonation tail and shock to detonation transition can both create single detonation wave or two opposite-direction detonation waves, depending on the wave hitting angle and the amount of fresh gas. All phenomena mentioned above affect the number of detonation waves in the combustion chamber. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.