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Literature Review Volume 10 Issue 3
Numerical simulation and validation with experimental results in a suddenly expanded flow at sonic Mach unity
Ambareen Khan, Mohammad Nishat Akhtar, Sher Afghan Khan
Received: July 05, 2026 | Published: July 20, 2026
Citation: Khan A, Akhtar MN, Khan SA. Numerical simulation and validation with experimental results in a suddenly expanded flow at sonic Mach unity. Aeron Aero Open Access J. 2026;10(3):126-135. DOI: 10.15406/aaoaj.2026.10.00260
Abstract
This study presents findings from numerical simulations at Mach unity and compares
them with experimental results under identical conditions. The flow from a converging
nozzle is exhausted into an enlarged duct with a 25 mm diameter, whereas the nozzle’s
inlet and exit diameters are 30 mm and 10 mm, respectively. The area ratio is 6.25. The
duct length-to-diameter ratio was varied from 6 to 1. The experiments were conducted with
five rectangular ribs spaced 25 mm apart. The aspect ratio of the rib was 3:1, 3:2, and 3:3.
Simulations, as well as the experimental results, show that for the rib aspect ratio, there is
a decrease in the base pressure.
In contrast, when the rib aspect ratio is 3:3, there is a considerable rise in the base pressure.
Hence, these two ribs, with an aspect ratio of 3:1, can be used for a combustion chamber
application. However, if the application is for external ballistics, then a 3:3 rib is the best
option.
Keywords: sudden expansion, L/D Ratio, area ratio, sonic Mach number, pressure loss
©2026 Khan, et al. This is an open access article distributed under the terms of the, which permits unrestricted use, distribution, and build upon your work non-commercially.