Shock-Structure Formation in Circular and Non-Circular Sonic Jets at Underexpanded Conditions

The generation of shock waves and their repercussions in high-speed vehicles are inevitable. Particularly, the hot plume from aircraft exhaust ejecting at a high speed, as well emitted aeroacoustic noise, have several consequences. Besides, occurrence supersonic core length emission screech noise mostly due to cells, prevailing jets. Therefore, understanding cell structures developed exit or rocket nozzles is vital improving mixing thereby characteristics. Essentially, non-circular nozzle shapes known for enhancing entrainment characteristics mitigating differential spreading over nozzle's perimeter. current study examines circular, elliptic, square jets various sonic underexpansion levels. In this investigation, geometries considered same area. Nozzle Pressure Ratio (NPR) was adjusted 3, 4, 5 achieve moderate highly conditions. shadowgraph visualization method used development cells axisymmetric asymmetric nozzles. It interesting observe that incident reflected exist only elliptic distinctive flow patterns along different axis planes. intercepting appears on jet minor rather than major direction. curvature wave found be greater circular jet. addition, symmetry plane diverges centerline, but diagonal direction converges. Moreover, estimated lengths using images were compared theoretical model where experimentally obtained results good agreement with values.