Analysis of noise radiation asymmetry of the Delta IV Heavy

The Delta IV Heavy rocket played a critical role in deploying high-profile payloads for the Department of Defense and NASA. Its triple-core, three-engine configuration presents an opportunity to study noise radiation patterns arising from its asymmetrical plume geometry. During NROL-70, the final flight of this historic rocket, acoustic data were collected from 22 locations spanning 0.5–9 km from Space Launch Complex 37 at Cape Canaveral. This paper’s objective is to investigate asymmetry in noise radiation resulting from the unmerged plumes of the rocket’s three distinct nozzles. Overall and frequency-dependent directivity patterns are calculated and discussed relative to jet and rocket noise literature. For example, previous studies of Atlas V and Space Launch System have shown frequency-dependentdirectivity in clustered nozzle configurations, with high-frequencyasymmetries observed. This research contributes to understanding these dynamics, offering insights into how engine configurations impact acoustic behavior and potential mitigation strategies. Such insights could inform future rocket and launch pad design.