Hysteretic Phenomenon of Underexpanded Moist Air Jet

Free underexpanded jets in a quiescent medium: A review

“…Eventually, some numerical studies seem to underline an hysteresis in this position in function of the pressure ratio [41,130,21,115].…”

“…The transient behavior of the fluid has not focused attention of many studies, be it theoretical [15] or experimental [16][17][18][19] or numerical [17,18,[20][21][22][23][24][25][26] ones. On the contrary, the steady state of the flow has been largely studied in the past , since it corresponded to the most often encountered situations.…”

“…Since the first numerical studies, and even now, the easiest way and the less expensive from a computational point of view is to consider the Reynolds Averaged Navier-Stokes equations (if obviously the flow is turbulent). Logically, this approach has been largely tested [110,31,132,63,138,243,34,216,218,116,45,220,84,21,22,55,[267][268][269][270][271]122,249], with the k ε − model in an overwhelming majority of papers (be it its incompressible formulation or some of the proposed compressibility corrections of the k CC ε − − class model). Even if this approach is acceptable to obtain the mean behavior of the flow, there are still some discrepancies between the results obtained with the various turbulence models (k ε…”

Experimental study on hysteresis phenomena of shock wave structure in an over-expanded axisymmetric jet

“…As in most of the engineering applications of supersonics jets, the working gas is usually steam or moist air and the moist air jets are qualitatively similar to dry air, but non-equilibrium condensation in moist air jet affects the shock configuration, reported by Baek et al [9] and Otobe et al [10]. Meanwhile, Kim et al [11] and Otobe et al [12] have investigated the effect of non-equilibrium condensation on the hysteresis phenomenon of under-expanded supersonic jets and reported that the moist air jet reduced the hysteretic phenomenon compared with the dry air jet, and the non-equilibrium condensation that occurs in the under-expanded moist air jet is responsible for these findings. However, only a few works have, to date, been devoted to the hysteresis phenomena for the reflection type of shock wave and for instance, the transitional pressure ratio between the regular reflection (RR) and…”

Gas-dynamic and mixing analysis of under-expanded hydrogen jets: effect of the cross section shape

“…For NPRs greater than 4, the onset of one or more strong normal shocks, the so-called Mach disks, has been deeply analysed. Position (Ashkenas & Sherman 1964;Lewis & Carlson 1964), diameter (Addy 1981;Hatanaka & Saito 2012) and hysteretic behaviour (Gribben, Badcock & Richards 2000;Irie et al 2003;Otobe et al 2009) are among the main features that have been examined. Conversely, the influence of the nozzle cross-section shape has received less attention by the researchers.…”