To reveal the flow characteristics of a supersonic underexpanded elliptic jet

the flow structures of underexpanded elliptic jets at the nozzle pressure ratio N of 14

24 and 40 were simulated using largeeddy simulation (LES) in combination with the high order hybrid schemes. The threedimensional (3D) flow characteristics and the evolution of underexpanded elliptic jet were illustrated from the results

and the reason for the different shock structures of the minor and major axis planes introduced by nonuniform curvature of the nozzle was discussed. Moreover

the results also found that the Mach shock reflection happened on the minor axis plane at N being 24

but regularreflection remained on the major axis plane. The shock structure of both major and minor axis planes were transferred into Mach reflection when N was 40. Therefore

the nozzle pressure ratio introducing the Mach shock reflection increases as the nozzle curvature radius becomes gentle.