Investigating Detonation-Shock Interference Using a Dual-Branch Model with Applications to RDEs

Rotating detonation engines (RDEs) offer higher thermal efficiency than conventional propulsion systems but often suffer from instability caused by destructive wave interference. This study compares a baseline dual-branch detonation configuration with a novel three-branch design that introduces a passive geometric phase delay to promote constructive interference. A reduced-order timing model informs the geometric design, which is evaluated through high-fidelity 2D reactive flow simulations in PeleC. The system is treated as a black-box and optimized using Bayesian Optimization, with maximum thrust computed from outlet flow data, serving as the objective. Latin Hypercube Sampling is used to train a Gaussian Process surrogate model that guides the search process for high-performing geometries. Results show that the three-branch configuration improves wave synchronization and enhances thrust output, demonstrating the potential of passive geometric control to improve RDE performance. To the authors' knowledge, this work represents the first application of phase-based timing control through geometry to mitigate wave interference in detonation-based propulsion systems.