@Article{fdmp.2026.084998,
AUTHOR = {Sher Afghan Khan,  Ridwan, Abdul Aabid, Khizar Ahmed Pathan, Muneer Baig},
TITLE = {Influence of Cavity Position on Flow Control at Large Mach Numbers: A CFD Analysis},
JOURNAL = {Fluid Dynamics \& Materials Processing},
VOLUME = {22},
YEAR = {2026},
NUMBER = {8},
PAGES = {0--0},
URL = {http://www.techscience.com/fdmp/v22n8/68708},
ISSN = {1555-2578},
ABSTRACT = {This study investigates the influence of a passive cavity flow-control strategy on base pressure in suddenly expanded supersonic flows through computational fluid dynamics (CFD) simulations. The flow configuration consists of a convergent-divergent (CD) nozzle discharging into an enlarged duct with an area ratio of 2.89. Simulations were performed for Mach numbers of 1.2, 1.4, 1.6, and 1.8, while the cavity was positioned upstream of the expansion at cavity locations corresponding to length-to-diameter ratios (L/D) ranging from 0.5 to 2.0 in increments of 0.5. The effects of nozzle pressure ratio (NPR), Mach number, duct length-to-diameter ratio, and cavity placement on base pressure were systematically examined. The results demonstrate that the cavity significantly enhances base pressure under the investigated operating conditions without adversely affecting the flow field. Base pressure is strongly influenced by Mach number, NPR, duct geometry, and cavity location. Among the configurations considered, the cavity positioned at 0.5D from the nozzle exit consistently provides the most effective pressure recovery across the range of Mach numbers, NPRs, and L/D ratios investigated. Furthermore, increasing NPR promotes stronger under-expanded jet conditions, with highly under-expanded flows observed at NPR = 6 and 8, leading to a corresponding increase in base pressure. These findings highlight the potential of cavity-based passive control for regulating base pressure in suddenly expanded supersonic flows.},
DOI = {10.32604/fdmp.2026.084998}
}