Alteration in Structure of Underexpanded Freejet Through Gas-Dynamic Perspective

Abstract

Studying the underexpanded jet has been essential for many fields of research because it might occur intentionally or spontaneously wherever a high-speed gas flow is possible. Therefore, an in-house compressible flow solver is employed to simulate an underexpanded sonic freejet. The behavior of the jet is examined in the near-field area, immediately downstream of the nozzle exit plane, to determine the parameters influencing the characteristics of the jet. The Mach reflection phenomenon is thoroughly studied, and a criterion is defined for the transformation from regular reflection to Mach reflection. Furthermore, the location and height of the Mach disk are found to be governed by the exit pressure ratio, the stagnation temperature, and the type of gas used. Although the temperature does not have a significant impact, the pressure ratio and specific heat ratio are found to affect the jet structure. The results obtained from the solver are compared with existing experimental results, highlighting the utility of the solver in probing the compressible flowfields.