Base flow dependence on nozzle cluster configuration during ascent for a VTVL launcher

This study investigates the influence of nozzle cluster configuration on the base flow during ascent in a simplified reusable launcher geometry. Three engine cluster layouts, featuring 7, 9, and 33 nozzles, were analyzed using CFD at selected points along the ascent trajectory. The results indicate that the 7- and 9-engine configurations exhibit similar base flow characteristics, including recirculation patterns, base pressure, and heat flux distributions. In contrast, the 33-engine configuration demonstrates distinct differences in these flow phenomena. These findings highlight the impact of nozzle arrangement on plume–plume interactions and flow separation behavior across varying Mach numbers. Future work will focus on evolving base configurations, incorporating recent design innovations such as recessed nozzles and structural fairings, to further assess their aerodynamic and thermal effects.